THE  LIBRARY 

OF 

THE  UNIVERSITY 

OF  CALIFORNIA 

LOS  ANGELES 

GIFT  OF 

Clarence  Staples 


f 


THE  STORY  OF 
WIRELESS  TELEGRAPHY 


THE  STORY  OF 
WIRELESS  TELEGRAPHY 


BY 
A.   T.    STORY 


WITH  FIFTY-SEVEN  ILLUSTRATIONS 


NEW    YORK 

D.    APPLETON    AND    COMPANY 
1904 


COPYRIGHT.  1904,  BY 
D.  APPLETON  AND  COMPANY 


Published  July, 


TK 


S88 


CONTENTS. 


PAGE. 

INTRODUCTION — Fairy-tales  of  Science — Early  Dreams  of 
Wireless  Telegraphy — The  Conduction  Method — In- 
duction —  The  Magnetic  Field  —  Electro-magnetic 
Waves — Electricity  and  Light— Clerk -Maxwell's  The- 
ory— Researches  of  Hertz — First  Hint  of  Etheric  Tele- 
graphy— Radiophony — Light  Telegraphy 9 


CHAPTER  I 

Steinhail's  Anticipation  of  Wireless  Telegraphy — Con- 
ductivity of  the  Earth — Its  Use  in  Place  of  a  Second 
Wire — Telegraphing  Through  the  Earth — Anticipa- 
tion of  the  Radiophone — Morse's  Experiments  in 
Wireless  Telegraphy— His  Results 18 


CHAPTER   II 

Wilkins's  Proposed  Method  of  Wireless  Communication 
with  France — Bering's  Experiments  with  Conduction 
through  Water — Lindsay — His  Electrical  Researches 
— Proposal  to  Telegraph  Across  the  Atlantic — His 
Method — Exoeriments  Across  the  Tay  and  Elsewhere  26 


CHAPTER  III 

Highton  and  his  Suggestions — Other  Experimenters  in 
Wireless  Telegraphy — A  Proposal  to  Communicate 
with  Besieged  Paris  by  Telegraphy  through  the  Water 
— Its  Necessity  Obviated  by  the  Armistice — Wireless 
Telegraphy  in  India — An  American  Dentist's  Concep- 
tion and  Experiments 40 


923902 


CONTENTS. 


CHAPTER  IV 

PAGE. 

Effect  of  Improvements  in  Cables — Invention  of  the  Tele- 
phone— Researches  of  Professor  Trowbridge  with — 
His  Experiments  with  Wireless  Telegraphy — Professor 
Graham  Bell's  Investigations — Dolbear's  Working 
with  Etheric  Waves — his  Anticipation  of  Marconi  .  48 


CHAPTER  V 

Telegraphic  Communication  with  Trains — A.  C.  Brown's 
Method — Willoughby  Smith  and  Phelps's  Suggestions 
— Successful  Application  of  the  Principle  by  Edison 
and  Gilliland — Edison's  Method  Applied  to  Ships — Sir 
William  Preece's  Researches — His  Experiments  on  the 
Solent — Across  the  Severn — At  Porthcawl — On  the 
Bristol  Channel — Loch  Ness — The  Island  of  Mull — 
His  Theory  of  the  Part  Played  by  the  Earth  in  Electro- 
magnetic Operations 65 


CHAPTER  VI 

Willoughby  Smith's  Experiments  in  Conduction  through 
Water  and  Earth — Smith  and  Granville's  Experiments 
at  the  Needles  Lighthouse — Application  of  their  Meth- 
od lo  the  Fastnet  Lighthouse — The  Investigations  of 
C.  A.  Stevenson  in  Electro-magnetic  Conduction  and 
Induction — Preece  and  Stevenson's  Experiments 
Awaken  Interest  on  the  Continent — Professor 
Rathenau's  Investigations — Evershed's  Experiments 
at  the  Goodwin  Lightship — Preece's  Experiments  at 
the  Skerries  and  Rathlin  Island — His  Views  as  to 
Earth  Conduction,  etc 85 


CHAPTER  VII 

Hertz's  Great  Discovery  of  Electromagnetic  Waves — His 
Apparatus — Clerk-Maxwell's  Hypothesis — Sir  Oliver 
Lodge  on  Maxwell  and  Hertz — The  Identity  of  Elec- 
tricity with  Light — Professor  Hughes  and  his  Re- 
searches— Sir  William  Crookes's  Prediction — Hughes's 
Account  of  his  Experiments — His  Wireless  Telegraphy 
— Discouragement  by  Scientific  Experts 101 


CONTENTS.  vii 

CHAPTER  VIII 

PAGE. 

The  Imperfect  Means  at  Hertz's  Command — The  Coherer 
and  its  History — Guitard — Varley — Onesti — Professor 
Branly — His  Radioconductor — Sir  Oliver  Lodge  and 
the  Coherer — His  Experiment  at  Oxford  in  1894 — 
Rutherford — Dr.  Muirhead — Captain  Jackson — Pro- 
fessor Bose — Professor  Righi — Lodge's  New  Coherer 
— Popoff's  Experiments 118 

CHAPTER  IX 

Gradual  Evolution  of  Wireless  Telegraphy — Marconi's 
Beginnings — Studies  at  Bologna — Arrival  in  England 
and  Introduction  to  Sir  William  Preece — His  Indebt- 
edness to  Righi  and  Others — His  Originality  in  Seeing 
Farther  than  Others — Description  of  his  System — His 
Oscillator — The  Coherer — The  Action  of  the  Whole 
Apparatus 130 

CHAPTER  X 

Marconi's  First  Experiments  in  England — Trials  on  the 
Bristol  Channel  —  Also  between  the  Needles  and 
Bournemouth — Experiments  at  Spezia — Valuable  Re- 
sults Obtained — Professor  Slaby's  Investigations  at 
Potsdam  and  Elsewhere — Further  Experiments  by 
Marconi — Wireless  Telegraphy  on  Board  the  Royal 
Yacht — Aerial  Communications  between  England  and 
France — British  and  French  Associations  for  the  Ad- 
vancement of  Science — Wireless  Telegraphy  at  the 
Naval  Maneuvers  —  Experiments  of  the  Brothers 
Lacarme — Communications  with  Balloons — Trials  by 
the  United  States  Navy  Board,  etc 147 

CHAPTER  XI 

The  American  Navy  Board  and  "Interference" — Wire- 
less Telegraphy  Experiments  at  Calvi,  Corsica — Syn- 
tony  Imperfectly  Attained — Sir  Oliver  Lodge  and 
Syntony — Signals  Received  at  St.  John's,  Newfound- 
land, from  Cornwall — The  Influence  of  Sunlight  upon 
Sending  Wires — Experiments  on  the  Carlo  Alberta — 
The  Apparatus  on  Board  and  at  Poldhu — Report  on 


viii  CONTENTS. 

PAGE. 

the  Results — Marconi's  Detector — Criticisms  on  the 
Report  —  Tapping  the  Messages — Syntony  again — 
Achievement  of  Transatlantic  Telegraphy  without 
Wires 164 


CHAPTER  XII 

The  System  of  Professor  Braun — The  Orling-Armstrong 
Method — Further  Particulars  of  the  Lodge-Muirhead 
System — Two  American  Wireless  Methods — That  of 
Dr.  Lee  de  Forest — Professor  Fessenden's  Discoveries 
—His  System — The  Future  of  Wireless  Telegraphy  .  180 


THE   STORY    OF 
WIRELESS   TELEGRAPHY 


INTRODUCTION 

Fairy  Tales  of  Science— Early  Dreams  of  Wireless  Tele- 
graphy— The  Conduction  Method — Induction — The 
Magnetic  Field— Electromagnetic  Waves — Electricity 
and  Light — Clerk -Maxwell's  Theory — Researches  of 
Hertz— First  Hint  of  Etheric  Telegraphy— Radio- 
phony — Light  Telegraphy. 

THE  past  century  witnessed  the  discovery  and 
development  of  many  (as  they  may  be  called) 
fairy  tales  of  science;  but  none  of  them — won- 
derful as  they  on  their  first  inception  seemed — 
strike  the  imagination  with  such  a  sense  of  the 
wonder-worker  at  play  as  the  marvels  of  Wire- 
less Telegraphy.  Electric  telegraphy  itself  was 
in  the  days  of  its  early  trials  and  successes  re- 
garded as  something  almost  necromantic;  and 
when  pioneers  in  science  began  to  speculate 
about  and  to  forecast  its  application  to  ocean  tele- 
graphy they  were  regarded  somewhat  as  moon- 
struck dreamers  and  phantasiasts  of  the  castle- 
in-the-air  variety.  But  ocean  telegraphy  came, 
and  then,  before  the  century,  of  whose  mid  de- 

9 


10    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

cades  it  was  a  triumph,  reached  its  end,  it  was 
followed  by  the  realization  of  another  dream, 
and  in  the  wonder-book  of  the  nineteenth  century 
was  written  another  fairy  tale  of  man's  triumph 
over  matter  and  over  space  in  the  achievement 
of  electric  telegraphy  without  wires. 

As  we  shall  see  in  the  following  pages,  the 
anticipation,  the  forecast  of  such  a  triumph,  was 
in  men's  minds  from  the  very  earliest  days  of 
telegraphy,  and  from  that  time  to  the  present 
keen  intellects  and  indomitable  wills — one  after 
another — never  ceased  to  be  turned  to  the  solu- 
tion of  the  problem.  First  they  sought  an 
answer  in  one  direction,  then  in  another.  Ever 
there  was  a  reply  sufficiently  alluring  to  keep  the 
ball  rolling — to  keep  the  ranks  of  the  investiga- 
tors full ;  and  the  achievements  of  one  generation 
of  workers  after  another  served  as  the  stepping- 
stones  over  which  their  successors  moved  to 
more  assured  successes,  until  finally  the  goal 
was  won,  if  we  can  consider  anything  as  final 
when  there  is  so  much  still  to  win  from  the 
unknown. 

There  were  in  the  earlier  half  of  the  last  cen- 
tury two  methods  familiar  to  men  of  science  by 
which  it  was  hoped  that  one  day  it  would  be 
possible  to  convey  messages  from  place  to  place 
without  the  use  of  wires.  One  of  these  methods 
was  that  known  as  Conduction,  by  which  the 
conductive  properties  of  the  earth  and  water  are 


CONDUCTION  AND   INDUCTION.  II 

turned  to  account  for  conveying  the  electric 
force ;  the  other  is  that  known  as  Induction,  by 
which  is  signified  the  property  an  electric  im- 
pulse has,  so  to  speak,  of  transferring  itself  from 
one  place  to  another. 

But  toward  the  end  of  the  century,  a  third 
principle  was  discovered,  which  suddenly  and 
most  unexpectedly  took  precedence  of  the  other 
two,  and  with  almost  startling  rapidity  was 
turned  to  account  as  a  means  of  electrically 
communicating  between  distant  places  without 
connection  by  wires.  This  third  method  is 
that  known  as  the  radiation  of  electromagnetic 
waves  through  space. 

It  will  be  convenient  here,  by  way  of  pre- 
liminary statement,  to  give  a  brief  explanation 
of  these  different  principles  of  electrical  action. 
To  take  Conduction  first — this  is  the  property 
certain  bodies  possess  of  allowing  heat,  sound, 
and  electricity  to  pass  through  them.  Thus  the 
felled  trunk  of  a  tree  is  a  good  conductor  of 
sound.  Metal  is  a  conductor  of  heat,  as  may  be 
proved  by  putting  one  end  of  a  metal  rod  in  the 
fire  and  taking  hold  of  the  other  end.  Elec- 
tricity finds  its  way  through  certain  substances 
in  the  same  manner,  and  in  proportion  to  the 
ease  of  such  passage  is  it  a  good  or  an  indiffer- 
ent conductor.  The  fact  that  copper  wire  was 
early  found  to  be  so  good  a  conductor  caused  it 
to  be  selected  as  the  best  material  for  ordinary 


12    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

telegraphic  purposes.  It  will  be  seen,  before  we 
have  proceeded  very  far  in  our  account  of  wire- 
less telegraphy,  that  water  and  the  solid  ground 
also  are  conductors,  and  it  was  the  discovery  of 
this  fact  which  turned  the  attention  of  investi- 
gators to  the  earth  as  a  means  of  telegraphing 
without  the  connecting  link  of  wires. 

What  Induction  is  may  best  be  explained  by  a 
simple  diagram  (Fig.  i).  Fig.  i  represents  two 
circuits,  in  the  first 
of  which  (A)  rep- 
resents a  galvanic 
battery  and  (B)  an 
interrupter,  by 
means  of  which  the 
current  of  electric- 
ity can  be  closed  or 
broken  at  will; 
while  in  the  other, 
FIG.  i.  which  remains 

always  closed,  a  galvanometer  (C)  is  included. 
Every  time  that  the  inducing  wire,  that  is 
the  one  containing  the  battery,  is  closed,  a 
short,  constant  current  is  set  up  in  the  other, 
or  induced,  wire  or  circuit,  and  this  secondary 
current  has  much  the  same  duration  as  that 
in  the  inductive  current.  If  the  latter  be  broken 
there  arises  in  the  induced  circuit,  a  cur- 
rent whose  direction  is  opposed  to  that  in  the 
primary  circuit,  and  this  phenomenon  is  repeated 


ELECTRO   MAGNETIC  WAVES.  13 

every  time  the  current  in  the  inducing  wire  is 
interrupted.  The  two  wires  may  be  a  few  feet 
or  several  miles  apart,  but  whether  the  one  or 
the  other,  induction  takes  place  all  the  same. 
Another  circumstance  connected  with  this  singu- 
lar appearance  is  that  directly  the  current  in  the 
primary  wire  begins  to  flow,  as  we  say,  what  is 
called  a  magnetic  field  is  set  up  all  round  it  and, 
so  far  as  we  understand,  is  the  cause  of  the  in- 
duction. But  the  whole  phenomenon  is  still  in- 
volved in  a  good  deal  of  mystery,  and  will  re- 
quire the  genius  of  another  Faraday,  whose 
peculiar  glory  it  is  to  have  first  discovered  the 
principle,  thoroughly  to  lay  bare  its  secret. 

The  third  method  of  telegraphing  without 
wires,  that  based  on  the  phenomenon  known  as 
electrostatic  waves,  is  the  most  surprising  of  all, 
and  up  to  the  present  time  has  produced  the 
most  wonderful  results,  although  it  is  quite  pos- 
sible that  they  may  be  outdone  in  the  future  by 
other  forms  of  electrical  action.  The  existence 
of  these  electromagnetic  waves  has  only  been 
known  since  1888,  and  the  story  of  their  dis- 
covery is  one  of  the  romances  of  science.  We 
shall  come  to  that  epoch-making  event  in  due 
course :  all  that  it  is  necessary  to  say  here  is  that 
by  means  of  disruptive  electrical  discharges 
electromagnetic  oscillations  are  set  up  in  the 
ether  with  which  all  space  is  filled,  and  that  upon 
these  oscillations,  or  waves,  by  instruments 


14    THE  STORY   OF  WIRELESS  TELEGRAPHY. 

properly  adapted  to  that  end,  signals  may  be 
transmitted  and  received,  as  in  ordinary  tele- 
graphy. 

These  waves  move  with  a  velocity  equaling 
that  of  light,  with  which  they  are  held  to  have 
an  intimate  connection,  and  vary  in  size  accord- 
ing to  the  strength  of  the  impulses  which  starts 
them  on  their  course, 
some  being,  as  it  were, 
mere    ripples    while 
others    stretch    to 

hundreds  and  even  thousands  of  miles  in  length. 
They  are  of  course  invisible  to  the  unaided  eye, 
though  the  eye  of  the  camera  has  seen  and  trans- 
fixed them  (Fig.  2). 

The  first  hint  of  the  existence  of  these  electro- 
magnetic waves  was  given  by  Professor  J.  Clerk- 
Maxwell  of  Cambridge,  who,  struck  by  the  value 
of  a  certain  coefficient,  very  important  in  the 
study  of  electrical  phenomena,  and  by  its  agree- 
ment with  the  figure  which  represents  the  veloc- 
ity of  the  propagation  of  light,  was  one  day 
strongly  impressed  with  the  extreme  likelihood 
that  light  and  electricity  were  essentially  the 
same.  Building  upon  this  apparent  identity, 
he  worked  out  an  hypothesis  in  regard  to  the 
constitution  of  the  medium  in  which  these  phe- 
nomena exist,  and  in  due  course,  as  a  French 
writer  puts  it,  "gave  to  the  world  the  edifice 
of  his  thought." 


ELECTRO  MAGNETIC  WAVES.  15 

Part  of  that  edifice  consisted  in  the  theory  that 
electricity,  like  light,  traverses  space  through 
the  medium  of  the  ether,  and  that  if,  by  a  dis- 
ruptive discharge,  a  magnetic  flux  is  created  in 
any  place  it  spreads  outward  or  extends  itself 
by  an  undulatory  motion  similar  to  what  we  see 
in  a  body  of  water  when  a  stone  is  dropped  into 
it.  Twenty-five  years  later  a  German  professor 
named  Heinrich  Hertz,  deeply  imbued  with  the 
teachings  of  Maxwell,  and  stimulated  by  a 
chance  observation  that  has  already  become 
classic,  conceived  the  idea  of  establishing  his 
theories  by  practical  experiment.  To  this  end 
he  devised  an  apparatus  peculiarly  adapted  to 
his  purpose,  and  with  it  not  only  succeeded  in 
making  a  brilliant  demonstration  of  the  truth  of 
Maxwell's  conception,  but,  going  still  further  in 
his  researches,  ended  by  giving  to  the  world  a 
means  of  communicating  through  space  on  the 
ether-piercing  rays  of  electricity. 

As  already  said,  this  magnificent  discovery 
was  given  to  the  world  in  1888.  It  was  barely 
made  public  ere  a  German  engineer  named 
Huber  questioned  Hertz  as  to  the  possibility  of 
making  use  of  the  electromagnetic  waves  as  a 
means  of  telegraphing  without  wires.  Hertz 
threw  cold  water  on  the  idea.  He  had  not 
grasped  the  full  significance  of  his  own  dis- 
covery ;  and  indeed  other  discoveries  and  inven- 
tions were  necessary  for  the  practical  realiza- 


1 6    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

tion  of  the  idea  thus  thrown  out.  But  there 
were  not  wanting  minds  who  perceived  some- 
thing of  the  scope  and  grandeur  of  the  role  this 
Maxwell-Hertz  discovery  was  destined  to  play 
in  the  near  future,  and  these,  as  we  shall  see, 
were  soon  at  work  moving,  unconsciously  for 
the  most  part,  toward  a  certain  end. 

I  have  mentioned  three  methods  of  turning 
electrical  energy  to  account  for  the  production 
of  wireless  telegraphy.  But  there  is  still  another 
which  ought  not  to  be  passed  over  in  such  an 
account  as  this,  the  more  especially  as  it  is  one 
that  may  yet  play  an  important  part  in  inter- 
communication between  place  and  place.  I  refer 
to  telegraphy  by  means  of  light  rays.  Radio- 
phony,  the  discovery  whereof  is  usually  attrib- 
uted to  Professor  Graham  Bell,  but  the 
honor  of  which  belongs  ,as  much  to  Mr.  A. 
C.  Brown,  is  based  upon  the  phenomena,  made 
known  in  1878,  that  selenium  possesses,  under 
certain  conditions,  the  property  that  when  placed 
under  a  ray  of  light  it  opposes  to  an  electrical 
current  a  less  resistance  than  when  it  is  in  the 
dark.  In  other  words,  it  is  a  better  conductor 
in  the  light  than  in  the  dark. 

The  discovery  appears  to  have  been  first  made 
by  one  of  Mr.  Willoughby  Smith's  assistants; 
although  Siemens  lighted  on  the  same  fact 
almost  contemporaneously.  Bell,  however,  in 
collaboration  with  Sumner  Tainter,  continued 


RADIOPHONY.  1 7 

and  extended  his  researches  with  a  view  to  ascer- 
taining whether  other  substances  possessed  the 
like  qualities,  with  the  result  that  he  found, 
among  others,  that  gold,  silver,  iron,  ivory, 
gutta-percha,  paper,  wood,  mica,  glass,  etc.,  were 
similarly  sensitive  to  light,  although  in  a  less 
degree  than  selenium. 

On  the  basis  of  this  observation  Bell  pro- 
ceeded to  devise  an  apparatus  whereby  a  ray  of 
light  could  be  thrown  upon  a  selenium  cell.  The 
cell  was  connected  with  a  battery  and  a  telephone 
in  a  circuit  in  such  a  way  that  every  change  in 
the  resistance  of  the  selenium,  and  the  therewith 
associated  change  in  the  strength  of  the  current 
in  the  telephone,  could  be  at  once  detected.  By 
shutting  off  the  light  rays  at  short  regular  inter- 
vals, signals  could  thus  be  transmitted,  and  these 
were  distinctly  repeated  in  the  telephone.  This 
delicate  instrument,  first  made  public  in  1880, 
was  originally  designated  the  photophone,  a 
name  which  was  subsequently  changed  to  radio- 
phone. The  same  idea  was  further  developed 
some  years  later;  but  of  this  invention  we  shall 
have  something  to  say  later  in  connection  with 
Hertz  and  his  investigations,  and  so  need  make 
no  further  reference  to  it  at  this  point. 


CHAPTER  I 

Steinheil's  anticipation  of  Wireless  Telegraphy— Conduc- 
tivity of  the  Earth — Its  use  in  place  of  a  second  wire 
—Telegraphing  through  the  Earth— Anticipation  of 
the  Radiophone — Morse's  experiments  in  Wireless 
Telegraphy — His  results. 

THE  story  of  Wireless  Telegraphy  presents  us 
with  a  number  of  names  of  men  who  may  be  said 
to  have  predicted  the  future  triumph  of  such  a 
form  of  communicating  between  place  and  place, 
if  we  may  accept  what  appear  to  have  been  mere 
wide-awake  dreams  as  prediction.  Setting  these 
aside,  however,  as  not  germane  to  our  subject, 
we  come,  in  the  scientific  records  of  1838,  to  the 
name  of  one  who  may  with  truth  be  said  to  have 
laid  the  foundation  of  telegraphy  without  wires. 
This  was  Prof.  C.  A.  Steinheil  of  Munich,  who 
in  the  year  named  gave  to  the  world  a  very 
clear  and  intelligent  anticipation  of  this  form  of 
electric  communication.  Being  associated  with 
Gauss — who,  along  with  Weber,  had  been  the 
first  to  demonstrate  the  practicability  of  electric 
telegraphy — during  the  time  that  he  was  con- 
structing his  famous  system  of  telegraphy  in 
Bavaria,  that  distinguished  scientist  suggested 
to  him  the  possibility  of  utilizing  the  two  lines 
iS 


STEINHEIL'S   EXPERIMENTS.  19 

of  a  railway  as  telegraphic  conductors.  Stein- 
heil  was  struck  with  the  suggestion,  and  put  it 
to  the  test  of  experiment  on  the  line  between 
Nuremberg  and  Fiirth.  The  attempt,  however, 
proved  a  failure  because  of  the  impossibility  of 
so  isolating  the  rails  as  to  prevent  the  passage 
of  the  electric  current  from  one  rail  to  another 
through  the  ground. 

But  if  Steinheil's  researches  turned  out  unsuc- 
cessful in  this  particular  respect,  they  neverthe- 
less led  to  a  most  important  discovery.  For  he 
found  that  the  conductivity  of  the  earth  was  so 
great  that  it  led  him  to  believe  that  it  might  be 
turned  to  advantage  for  the  return  current  in 
place  of  the  second  wire  previously  used.  The 
experiments  instituted  to  test  the  truth  of  this 
inference  proved  entirely  successful,  and  he  was 
thus  enabled,  by  the  introduction  of  this  earth 
circuit,  to  make  one  of  the  most  important  con- 
tributions toward  successful  telegraphy. 

In  the  account  Steinheil  gives  of  his  discovery, 
and  the  practical  use  he  made  of  it,  he  says : 
"  It  appeared  of  especial  interest  to  inquire  into 
the  laws  of  dispersion,  whereby  the  ground, 
whose  mass  is  limited,  is  acted  upon  by  the  pas- 
sage of  the  galvanic  current.  The  galvanic  cur- 
rent cannot  confine  itself  merely  to  the  portions 
of  earth  situated  between  the  two  ends  of  the 
wire,  but  must  spread  out  indefinitely  on  every 
hand,  and  it  only  depends,  therefore,  on  the  rela- 


20    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

tion  in  which  this  law  as  to  the  excitation  of  the 
ground  stands  to  the  distance  of  the  exciting 
terminations  of  the  wire,  whether  any  metallic 
connection  at  all  is  necessary  for  carrying  on 
telegraphic  communication. 

"  I  can  here  only  briefly  state  that  I  have  dis- 
covered a  means  of  putting  the  law  of  this  phe- 
nomenon to  the  test  of  experiment,  with  the  re- 
sult that  it  is  seen  that  the  excitation  quickly  de- 
clines as  the  distance  from  the  exciting  conductor 
is  increased. 

"  Appliances  can  indeed  be  constructed  ( Stein- 
heil  goes  on  to  say),  in  which  the  indicator, 
having  no  metallic  connection  with  the  multi- 
plier, generates  currents  in  that  multiplier, 
through  the  excitation  of  the  ground  alone,  suffi- 
cient to  cause  visible  deflections  of  the  bar.  This 
is  a  hitherto  unobserved  fact,  and  may  be  classed 
among  the  most  extraordinary  phenomena  that 
science  has  revealed  to  us.  It  only  holds  good, 
however,  for  small  distances,  and  we  must  leave 
it  to  the  future  to  decide  whether  it  will  ever  be 
possible  to  telegraph  to  great  distances  entirely 
without  metallic  connection.  For  distances  up 
to  fifty  feet,  I  have  proved  the  possibility  of  such 
electric  communication  by  experiment.  For 
greater  distances  we  can  only  conceive  it  pos- 
sible by  augmenting  the  power  of  the  galvanic 
induction,  or  by  appropriate  multipliers  con- 
structed for  the  purpose,  or,  finally,  by  increas- 


STEINHEIL'S   EXPERIMENTS.  21 

ing  the  surface  of  contact  presented  by  the  ends 
of  the  multipliers.  In  any  case  the  phenomenon 
is  worthy  of  our  best  attention,  and  it  may  not 
perhaps  be  without  influence  upon  the  theoretic 
view  we  may  form  in  regard  to  the  nature  of 
galvanism  itself." 

Thus  was  the  possibility  of  wireless  telegraphy 
first  scientifically  demonstrated.  Steinheil's  ex- 
periments, however,  did  not  lead  him  in  the  end 
to  any  very  sanguine  anticipations  in  regard  to 
the  practical  value  of  such  telegraphy,  and  in 
referring  to  the  subject  in  his  Application  of 
Electro-Magnetism,*  he  makes  the  following  ob- 
servation :  "  The  spreading  of  the  galvanic  effect 
is  proportional,  not  to  the  distance  of  the  point  of 
excitation,  but  to  the  square  of  this  distance ;  so 
that,  at  the  distance  of  fifty  feet,  only  exceedingly 
small  effects  can  be  produced  by  the  most  power- 
ful electrical  effect  at  the  point  of  excitation. 
Had  we  the  means  which  could  stand  in  the  same 
relation  to  electricity  that  the  eye  stands  to  light, 
nothing  would  prevent  our  telegraphing  through 
the  earth  without  conducting  wires ;  but  it  is  not 
probable  that  we  shall  ever  attain  that  end." 

While  Professor  Steinheil's  mind  was  thus 
intent  upon  the  subject  of  wireless  telegraphy  he 
struck  out  another  idea  in  connection  therewith, 
and  thereby  curiously  anticipated  Graham  Bell's 
radiophone.  His  proposed  method  was  to  direct 
*  Die  Anwendung  des  Electromagnetismus. 


22    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

radiant  heat  upon  a  thermoelectric  pile  by  means 
of  condensing  mirrors,  thus  calling  a  galvanic 
current  into  action,  which  in  its  turn  could  be 
employed  to  bring  about  declinations  of  a  mag- 
netic needle.  Though  Steinheil  foresaw  consid- 
erable difficulties  in  the  working  out  of  this  prin- 
ciple, he  held  that  they  were  not  insuperable. 
Others  since  his  time  have  given  much  time  and 
thought  to  the  subject;  but  it  would  take  us  too 
far  away  from  the  main  line  of  investigation 
regarding  wireless  telegraphy  to  go  into  the  mat- 
ter here. 

Following  Steinheil,  little  beyond  some  scien- 
tific dreaming  was  done  until  Professor  S.  F.  B. 
Morse,  Superintendent  of  Telegraphs  to  the 
Government  of  the  United  States,  inventor  of 
the  telegraphic  alphabet  known  by  his  name, 
began  to  experiment  with  a  view  to  seeing  what 
could  be  done  by  way  of  dispensing  with  arti- 
ficial conductors.  His  first  experiments  were 
made  in  the  autumn  of  1842,  when,  at  the  request 
of  the  American  Institute,  he  undertook  to  give 
to  the  public  of  New  York  a  demonstration  of 
the  practicability  of  his  telegraph,  and  for  that 
purpose  laid  wires  between  Governor's  Island 
and  Castle  Garden,  a  distance  of  a  mile.  To  his 
intense  mortification,  however,  soon  after  he  had 
begun  operations,  his  purpose  was  frustrated  by 
the  accidental  destruction  of  a  part  of  his  con- 
ductors by  a  vessel  which  drew  them  up  with  its 


MORSE'S   EXPERIMENTS.  23 

anchor  and  cut  them  off.  The  accident,  how- 
ever, proved  to  be  a  fortunate  circumstance,  as 
it  put  into  Morse's  head  the  idea  of  arranging 
his  wires  along  the  banks  of  the  stream,  and  so 
trying  if  the  water  itself  would  conduct  the  elec- 
tricity across. 

His  first  experiments  according  to  this  new 
method  were  made  in  December,  1842,  across  a 
canal  at  Washington,  and  proved  eminently  suc- 
cessful. These  experiments  were  continued  by 
Professor  Gale  on  Morse's  behalf,  and  in  writing 
to  the  Secretary  of  the  United  States  Treasury 
on  the  subject  of  his  experiments,  on  December 
23,  1844,  Morse  says :  "  The  simple  fact  was 
then  ascertained  that  electricity  could  be  made 
to  cross  a  river  without  other  conductors  than 
the  water  itself." 

Morse  repeated  his  experiments  on  a  larger 
scale  in  the  autumn  of  1844,  his  aim  then  being, 
as  he  explains,  to  ascertain  the  law  ruling  the 
passage  of  electricity  across  a  body  of  water. 
The  nature  of  his  experiment  will  be  understood 
from  the  annexed  diagram  (Fig.  3). 

A,  B,  C,  D  are  the  banks  of  the  river;  P,  R 
is  the  battery ;  G  is  a  galvanometer ;  W ' ,  W  are 
the  wires  along  the  banks,  connected  with  copper 
plates,  f,  g,  h,  i,  which  are  placed  in  the  water. 
According  to  Morse,  the  electricity,  generated  by 
the  battery,  passes  from  the  positive  pole  P  to  the 
plate  h,  across  the  river  through  the  water  to 


24    THE  STORY  OF  WIRELESS  TELEGRAPHY. 

plate  i,  and  thence  around  the  coil  of  the  galvan- 
ometer to  plate  f,  across  the  river  again  to  plate 
g,  and  thence  to  the  other  pole  of  the  battery  R, 
to  complete  the  circuit. 

These  experiments  were  made  with  different 
lengths  of  wire  laid  along  the  banks  of  the  canal, 
and  with  batteries,  the  number  of  elements  com- 
posing which  were  of  different  strengths.^  In  the 

v-A 


FIG.  3.  , 


result  it  was  found  that  the  quantity  of  elec- 
tricity which  passed  from  one  bank  of  the  stream 
to  the  other  stood  in  direct  relationship  to  the 
size  of  the  plates  sunk  in  the  water,  as  well  as 
to  the  distance  of  the  plates  on  the  same  side  of 
the  river  from  each  other.  From  these  and 
other  experiments  it  was  deduced  that  this  dis- 
tance should  be  three  times  greater  than  that 
from  shore  to  shore.  A  greater  distance  than 
that  did  not  give  any  increase  of  power. 

Similar  experiments  were  carried  out  by 
Messrs.  Vail  and  Rogers,  two  of  Professor 
where  the  distance  separating  the  two  circuits 
Morse's  assistants,  across  the  Susquehanna  River, 


VAIL   AND    ROGERS  25 

was  nearly  a  mile,  and  with  complete  success. 
It  is  curious  to  note  that,  in  his  communication 
to  the  Secretary  of  the  Treasury,  Morse  remarks 
that  "  experience  alone  can  determine  whether 
lofty  spars,  on  which  wires  may  be  suspended, 
erected  in  the  rivers,  may  not  be  deemed  the 
most  practical." 

A  full  account  of  these  experiments  is  given 
in  Alfred  Vail's  American  Electromagnetic  Tele- 
graph, published  in  1845,  and  reprinted  in  the 
Electrical  World,  June  29,  1895. 


CHAPTER  II 

Wilkins'  proposed  method  of  wireless  communication 
with  France — Bering's  experiments  with  conduction 
through  water — Lindsay — His  electrical  researches — 
Proposal  to  telegraph  across  the  Atlantic — His  method 
— Experiments  across  the  Tay  and  elsewhere. 

THE  next  worker  in  the  field  of  wireless  tele- 
graphy of  whom  we  have  any  knowledge  is  Mr. 
J.  W.  Wilkins,  whose  experiments  were  begun 
in  1845.  Wilkins  was  associated  for  many  years 
with  Messrs.  Cooke  and  Wheatstone,  the  pioneers 
of  electric  telegraphy  in  Great  Britain ;  and  in  a 
letter  appearing  in  the  Mining  Journal,  March 
28,  1849,  he  clearly  sets  forth  a  method  whereby, 
as  he  conceived,  telegraphic  communication 
might  be  established  between  England  and 
France,  which  the  submarine  cable  had  not  at 
that  time  joined.  As  this  letter,  from  the  sug- 
gestions it  contains,  is  of  great  importance  in  the 
history  of  wireless  telegraphy,  it  will  be  well  to 
give  almost  entire  the  writer's  description  of  the 
method  by  which  he  proposed  to  carry  out  his 
"  theory  upon  which  a  telegraphic  communica- 
tion may  be  made  between  England  and  France 
without  wires." 

"  I  take  for  certain,"  he  proceeds — "  as  experi- 
26 


WILKINS'   SUGGESTION.  27 

ments  I  have  made  have  shown  me — that  when 
the  positive  and  negative  poles  of  a  battery  are 
dipped  into  or  connected  with  any  conducting 
medium,  the  electricity  around  the  positive  pole 
is  positive,  being  diffused  in  radial  lines,  and  the 
part  around  the  negative  pole  is  negative  in 
radial  lines  converging  toward  it,  supplying  the 
electricity  requisite  for  the  decomposition  of  the 
substances  composing  the  battery.  This  under- 
stood, it  is  evident  that  when  a  positive  radial 
line  sets  out  from  the  junction  of  the  battery 
with  the  earth  it  makes  its  way  to,  or  is  attracted 
by  the  nearest  negative  portion  of  earth,  at  last 
meeting  the  negative  pole  of  the  battery,  restor- 
ing the  equilibrium.  From  this  it  appears  that 
the  first  portion  of  electricity  will  pass  in  a 
straight  line  between  the  two  poles,  being  the 
shortest  between  them,  and  the  rays  will  then 
form  curves  between  the  poles  until,  by  reason 
of  increasing  distance,  they  are  no  longer  in- 
fluenced by  one  another,  without  a  better  me- 
dium of  conduction  be  interposed  in  their  cir- 
cuit. 

"  It  is  natural  to  suppose  that  all  parts  of  the 
earth  are  not  of  one  uniform  density ;  if  so,  then 
some  parts  are  positive,  and  others  negative. 
Then  from  this  it  is  easy  to  see  that  some  of  the 
electricity  flowing  from  the  positive  pole  is  the 
means  of  restoring  equilibrium  to  negative  por- 
tions of  the  earth — not  necessarily  rendered  so 


28     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

by  the  negative  pole  of  the  battery;  and  also 
positive  portions,  for  the  same  reason,  rendered 
neutral  or  negative. 

"  These  rays  of  electricity  may  be  collected  in 
a  certain  quantity  between  the  point  whence  they 
start,  and  where  they  are  rendered  neutral,  and 
by  the  interposition  of  a  metallic  medium  that 
shall  offer  less  resistance  than  the  water  or  earth 
— obviously  the  nearer  the  battery  the  greater 
the  chance  of  collecting  them.  I  do  not  antici- 
pate the  distance  of  twenty  miles  is  at  all  too 
much  (with  the  means  we  can  use  to  compen- 
sate it)  to  collect  a  sufficient  quantity  of  current 
to  be  useful  for  telegraphic  purposes.  Still,  the 
quantity  would  be  small,  and  with  the  present 
telegraphic  instruments  would  not  be  detected  at 
all.  The  current  in  the  wire  (of  the  instrument 
used)  must  be  detected — not  by  its  amount,  but 
that  it  exists  in  any  quantity,  however  small.  If, 
then,  electricity  can  be  collected  in  France,  simul- 
taneously with  a  discharge  from  a  battery  in 
England,  all  that  is  required  is,  to  find  out  what 
to  do  with  it,  so  that  it  shall  indicate  its  presence. 

"  I  will  now  lay  before  you  the  arrangement  I 
propose  for  carrying  out  this  design. 

"  No.  i . — Upon  one  shore  I  propose  to  have  a 
battery  that  shall  discharge  its  electricity  into  the 
earth  or  sea,  having  a  distance  of  some  five,  ten, 
or  perhaps  twenty  miles — as  the  case  may  be — 
between  the  poles. 


WILKINS'   SUGGESTION.  29 

"No.  2. — Let  a  similar  length  of  wire  be 
erected  on  the  opposite  coast,  as  near  to,  and  as 
parallel  with  it  as  possible ;  having  its  ends  dip- 
ping into  the  sea  or  earth. 

"  No.  3. — Within  the  above  circuit  have  an  in- 
strument consisting  of  about  ten  or  twenty,  or 
more,  square  or  round  coils  of  finest  wire,  of  best 
conductibility,  suspended  on  points  or  otherwise, 
being  part  of  circuit  No.  2.  Suspend  this  coil 
before  or  between  the  poles  of  an  electro,  or  per- 
manent magnet  or  magnets,  and  in  either  case 
any  current  passing  through  the  coil  will  be  indi- 
cated by  its  moving  or  shifting  position.  This 
would  then  constitute  the  telegraph.  It  would 
now  only  depend  upon  the  distance  between  the 
poles  of  the  battery,  in  one  case,  and  the  ends  of 
the  circuit  wire  in  the  other,  together  with  the 
lightness  of  the  coils  of  wire  used — having  ref- 
erence to  their  number — and  the  power  of  the 
magnet  or  magnets  used  to  deflect  it ;  although 
that  would  be  easy  of  adjustment,  and  when  once 
done,  are  certain  to  be  of  continuance — at  all 
events,  much  more  so  than  a  submerged  wire 
across  the  Channel. 

"  I  hope  some  one  will  take  up  this  sugges- 
tion, and  carry  it  out  practically,  to  a  greater  ex- 
tent than  my  limited  experiments  have  enabled 
me ;  for,  of  its  truth,  for  long,  as  well  as  short 
distances,  I  am  satisfied,  and  want  of  means  only 
prevents  me  carrying  it  out  at  once.  I  venture 


30     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

to  say  what  I  have,  on  an  experience  in  electricity 
of  ten  years,  and  a  practical  acquaintance  with 
electric  telegraphs  of  nearly  five  years." 

This  letter,  and  the  theory  it  contained,  ap- 
pears to  have  been  forgotten  until,  in  a  letter  in 
the  Electrician  (July  19,  1895),  Wilkins  directed 
attention  to  it.  "  In  1845  "  (he  writes)  "  while 
engaged  on  the  only  long  line  of  telegraph  then 
existing  in  England,  my  observation  led  me  to 
question  the  accepted  theory  that  currents  of 
electricity,  discharged  into  the  earth  at  each  end 
of  a  line  of  telegraph,  sped  in  a  direct  course — 
instinctively,  so  to  say — through  the  interven- 
ing mass  of  ground  to  meet  a  current  or  find  a 
corresponding  earth-plate  at  the  other  end  of 
it  to  complete  the  circuit.  I  could  only  bring 
myself  to  think  that  the  earth  acted  as  a  reservoir 
or  condenser — in  fact,  receiving  and  distributing 
electricity  almost  superficially  for  some  certain 
or  uncertain  distance  around  the  terminal  earths, 
and  that  according  to  circumstances  only.  A 
year  later,  while  occupied  with  the  installation 
of  telegraphs  for  Messrs.  Cooke  and  Wheatstone, 
a  good  opportunity  offered  of  testing  this  matter 
practically  upon  lengths  of  wire  erected  on  both 
sides  of  a  railway. 

"  To  succeed  in  my  experiment,  and  detect  the 
very  small  amount  of  electricity  likely  to  be  avail- 
able in  such  a  case,  I  evidently  required  the  aid 
of  a  very  sensitive  galvanometer,  much  more  so 


BERING   AND   LINDSAY.  31 

indeed  than  the  long  pair  of  astatic  needles  and 
coil  of  the  Cooke  and  Wheatstone  telegraph, 
which  was  then  in  universal  use  as  a  detector. 
The  influence  of  magnetism  upon  a  wire  convey- 
ing an  electric  current  at  once  suggested  itself  to 
me,  and  I  constructed  a  most  sensitive  instrument 
on  this  principle,  by  which  I  succeeded  in  obtain- 
ing actual  signals  between  lengths  of  elevated 
wires  about  120  feet  apart.  This,  however,  sug- 
gested nothing  more  at  the  moment  than  that  the 
current  discharged  from  the  earth-plates  of  one 
line  found  its  way  into  the  earth-plates  of  an- 
other and  adjacent  circuit,  through  the  earth. 

"  Later  on  I  had  other  opportunities  of  veri- 
fying this  matter  with  greater  distances  between 
the  lines  of  wire,  and  ultimately  an  instance  [pre- 
sented itself]  in  which  the  wires  were  a  consid- 
erable distance  apart,  and  with  no  very  near  ap- 
proach to  parallelism  in  their  situation.  Then 
it  was  that  it  entered  my  head  that  telegraphing 
without  wires  might  be  a  possibility." 

It  is  of  interest  to  note  that  the  instrument 
which  Wilkins  conceived  as  a  means  of  detecting 
the  current  impulses  anticipated  the  siphon  re- 
corder of  Lord  Kelvin,  as  well  as  the  Deprez- 
D' Arson val  instrument  so  much  used  on  the  Con- 
tinent, and  others. 

These  researches  on  the  part  of  Wilkins  were 
followed  in  the  earlier  half  of  the  next  decade  by 
two  series  of  highly  interesting  experiments  con- 


32     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

ducted  respectively  by  George  E.  Bering  and 
James  Bowman  Lindsay.  It  is  perhaps  impos- 
sible now  to  determine  which  of  these  investi- 
gators was  actually  first  in  the  field,  but  as  Ber- 
ing was  the  first  to  take  out  a  patent  (August 
:5>  J853)  f°r  transmarine  telegraphs  he  seems 
to  claim  priority  of  attention.  In  his  specifica- 
tion Bering  sets  forth  several  alternative  methods 
for  effecting  his  purpose,  one  of  which  consists 
in  establishing  circuits  composed  of  uninsulated 
or  partially  insulated  conductors,  and  in  part  of 
the  conducting  property  of  thfLsea,  across  which 
communication  is  to  be  made,  or  of  the  earth  or 
the  moisture  contained  therein  in  the  case  of  land 
telegraphs.  "  For  this  purpose  the  connections 
are  effected  at  such  a  distance  in  a  lateral  direc- 
tion that  a  sufficient  portion  of  the  current  will 
pass  across  the  water  or  earth  space  and  enter 
the  corresponding  wire  connection  at  the  other 
extremity." 

Bering  tested  his  method  across  the  river 
Mimram,  at  Locksley,  Herts,  with  parallel  wires 
of  galvanized  iron,  laid  at  a  distance  of  about 
thirty  feet  apart,  and  a  small  battery  composed 
of  two  or  three  Smee  cells,  with  which  apparatus 
he  was  successful  in  obtaining  understandable 
signals. 

Lindsay  was  a  man  in  many  respects  very 
different  to  the  others  that  have  been  named. 
They  were  practical  men  and  for  the  most  part 


LINDSAY'S   EDUCATION.  33 

pioneers  in  the  actual  work  of  telegraph-laying 
and  operating.  Lindsay,  on  the  contrary,  was  a 
scholar,  a  man  deeply  read  in  many  branches  of 
learning,  and  with  a  mind  admirably  adapted  for 
scientific  research.  He  seemed  to  possess  the 
intellectual  tentacles  which  are  forever  probing 
ahead  on  the  borderland  of  the  unknown  and 
pushing  forward  lines  of  light  into  its  dim  and 
unfathomed  spaces. 

A  linen-weaver  by  trade,  he  early  showed  such 
a  devotion  to  books  that  his  parents  saw  fit  to 
send  him  to  St.  Andrews  University.  There, 
although  hitherto  self-taught,  he  soon  distin- 
guished himself  by  his  abilities,  and  won,  before 
his  four  years'  course  was  concluded,  the  premier 
place  in  the  mathematical  and  physical  branches 
of  science.  It  was  his  intention,  apparently,  to 
enter  the  Church,  and  he  devoted  himself  very 
assiduously  to  theology  with  that  object  in  view; 
but  his  mind  appears  to  have  run  too  much  in 
the  groove  of  science  and  investigation  for  him 
to  be  content  in  the  restricted  sphere  of  a  min- 
ister, even  if  he  had  become  one,  which  he  never 
did. 

For  a  time  during  his  University  career  he 
appears  to  have  resumed  his  occupation  of  weav- 
ing in  the  summer  vacation ;  but  later  he  devoted 
himself  to  teaching,  and  to  that  profession  the 
remainder  of  his  life  was  more  or  less  given — 
for  a  time  as  mathematical  lecturer  at  the  Watt 
3 


34    THE  STORY   OF  WIRELESS  TELEGRAPHY. 

Institution,  Dundee,  later  as  teacher  in  the  Dun- 
dee Prison  at  a  salary  of  £50  a  year,  a  post  which 
he  held  from  1841  to  1858.  In  the  latter  year 
he  was,  on  the  recommendation  of  Lord  Derby, 
at  that  time  Prime  Minister,  granted  a  pension 
of  £100  a  year  in  recognition  of  his  great  learn- 
ing and  extraordinary  attainments. 

Much  of  Lindsay's  time  seems  to  have  been 
wasted  on  dead  languages,  and,  if  we  may  be 
permitted  the  comparative,  "  deader "  chronol- 
ogy. But  for  that — and  his  poverty — his 
achievements  in  the  field  of  electrical  science, 
great  as  they  were,  might  have  been  much  more 
considerable.  According  to  his  own  statement, 
he  first  turned  his  thoughts  to  electrical  investi- 
gation in  1832,  and  was  for  a  time  undecided 
whether  he  should  devote  his  attention  to  elec- 
tricity as  a  source  of  power,  of  light,  or  of  tele- 
graphic communication.  He  decided  in  favor  of 
light,  and  his  success  in  that  direction  was,  we 
are  told,  so  undoubted  that  he  was  able  (in  1835) 
to  light  his  one  little  room  by  electricity.  A  year 
before  that  he  had  predicted  in  a  public  print 
that  "  in  a  short  time  houses  and  towns  would  be 
lighted  by  electricity,"  that  they  would  be  heated 
by  it  also,  and  that  machinery  would  be  driven 
by  it  "  at  a  trifling  expense." 

Having  gone  thus  far  in  his  investigations 
with  regard  to  electric  lighting,  Lindsay,  after 
some  years  devoted  to  other  and  less  illuminating 


LINDSAY'S   PROPHESY.  35 

labors,  turned  his  attention  to  electric  telegraphy. 
It  is  not  necessary  here  to  refer  at  length  to  his 
ideas  regarding  transatlantic  telegraphy.  Such 
a  thing  in  1845  was  a  dream,  but  it  was  such  a 
dream  as  Lindsay  had  the  prescience  to  see  might 
one  day  be  realized.  His  conception  was  that 
the  thing  could  be  done  by  means  of  a  naked 
wire  and  earth  batteries.  According  to  his  own 
statement  he  had  "  proved  the  possibility  "  of  the 
method  he  suggested,  "  by  a  series  of  experi- 
ments." He  was  not,  of  course,  the  first  to  make 
such  experiments ;  for,  as  we  have  seen,  Stein- 
heil  in  1838,  and  Morse  in  1842,  to  say  nothing 
of  others,  had  successfully  tested  the  feasibility 
of  signaling  with  uninsulated  wire  and  without 
wire.  But  to  him  is  apparently  due  the  credit 
of  having  first  suggested  the  possibility  of  tele- 
graphing across  the  Atlantic  by  combining  the 
two  principles. 

But  Lindsay's  "  intellectual  tentacles  "  led  him 
a  considerable  step  beyond  this,  although  it  was 
not  until  1853  that  he  made  his  conception 
known  to  the  world.  In  the  month  of  March  in 
that  year  he  delivered  a  lecture  in  Dundee  on  the 
subject  of  telegraphic  communication,  and  in  the 
course  of  his  remarks  he  made  it  perfectly  clear 
that  he  had  conceived  the  possibility  of  tele- 
graphy without  wires.  By  a  peculiar  arrange- 
ment of  wires  at  the  sides  of  rivers  or  seas  (he 
said)  the  electric  influence  could  be  made  to  pass 


36    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

through  the  water  itself.  Thence  submerged 
wires,  such  as  those  then  used  for  telegraphic 
purposes  between  England  and  France,  were  no 
longer  necessary.  In  June,  1854,  Lindsay  pat- 
ented his  method,*  and  in  the  opening  clause  of 
his  specification,  he  describes  his  invention  as 
consisting  of  "  a  mode  of  transmitting  tele- 
graphic messages  by  means  of  electricity  or  mag- 
netism through  and  across  water  without  sub- 
merged wires,  the  water  being  made  available 
as  the  connecting  and  conducting  medium." 

The  annexed  diagram  (Fig.  4)  explains  Lind- 
say's method.  A,  A  show  the  position  of  a  bat- 
tery and  telegraph  instrument,  to  which  are  at- 
tached two  wires  terminating  in  metal  plates 
or  balls  placed  in  the  water  z,  at  a  certain 
distance  apart,  according  to  the  width  of  the 
water  to  be  traversed ;  B,  B  represent  the  bat- 
tery and  instrument  on  the  opposite  side  of  the 
water ;  C,  E,  D,  F  are  metallic  and  charcoal  ter- 
minators ;  C,  H,  I,  K  insulated  wires  connecting 
the  terminators,  batteries,  and  instruments,  as 
indicated. 

If  it  is  required  to  send  a  message  from  A,  it 
is  evident  that  the  current  will  have  two  courses 
open  to  it,  the  one  being  directly  through  the 
water  from  C  to  D,  the  other  across  the  water 
from  C  to  E,  along  the  wires  I,  K,  through  the 
instrument  B,  and  so  back  from  F  to  D.  "  Now, 
*  Lindsay's  patent  is  numbered  1942,  Bering's  1909. 


LINDSAY'S   METHOD.  37 

I  have  found  (says  Lindsay)  that  if  each  of  the 
two  distances  C  D  and  E  F  be  greater  than  C  E 
and  D  F,  the  resistances  through  C  E  and  D  F 
will  be  so  much  less  than  that  through  the  water 
between  C  and  D,  that  more  of  the  current  will 


FIG.  4. 

pass  across  the  water,  through  the  opposite 
wires,  and  recross  at  F,  than  take  the  direct 
course  C  D  ;  or,  more  correctly  speaking,  the  cur- 
rent will  divide  itself  between  the  two  courses  in 
inverse  ratio  to  their  resistances." 

Lindsay's  specification  provides  that  the  dis- 
tance between  the  submerged  plates  shall,  when 
practicable,  be  greater  than  that  across  the  water ; 
but  when  that  is  not  possible,  and  there  is  danger, 
in  consequence,  of  the  current  of  electricity  tak- 
ing the  shorter  cut  from  C  to  D,  in  place  of  the 


38     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

longer  one,  as  would  thus  be,  from  C  to  E,  he 
proposes  to  increase  the  size  of  the  plates  and  at 
the  same  time  to  augment  the  force  of  the  bat- 
teries, "  so  as  to  compel  a  sufficient  portion  of 
the  current  to  cross." 

Lindsay  made  public  trials  of  his  method  in 
one  of  the  docks  at  Dundee,  and  subsequently  at 
Glencarse  on  the  Tay,  where  the  river  is  nearly 
three-quarters  of  a  mile  wide,  and  where  he  was 
successful  in  getting  deflections  of  the  needle 
from  one  side  to  the  other.  These  experiments 
were  repeated  at  Woodhaven  on  the  Tay,  where 
the  river  is  nearly  two  miles  across,  and  at 
various  other  places,  generally  with  equal  suc- 
cess, although  on  one  occasion,  at  Liverpool,  he 
met  with  a  signal  and  unaccountable  failure. 

In  1859,  when  the  British  Association  held  its 
annual  meeting  at  Aberdeen,  Lindsay  read  a 
paper  before  that  body  "  On  Telegraphing  with- 
out Wires,"  which  appears  to  have  won  the 
hearty  approval  of  Lord  Rosse,  the  president  of 
the  electrical  section,  as  well  as  of  Faraday,  and 
other  leading  scientific  men. 

An  abstract  of  the  paper  appeared  in  the  Dun- 
dee Advertiser,  in  which  it  was  stated  that  "Ex- 
periments had  shown  that  only  a  fractional  part 
of  the  electricity  generated  goes  across,  and  that 
the  quantity  that  thus  goes  across  can  be  in- 
creased in  four  ways  :  ( I )  by  an  increased  bat- 
tery power;  (2)  by  increasing  the  surface  of  the 


LINDSAY'S   LAST  EXPERIMENT.  39 

immersed  sheets;  (3)  by  increasing  the  coil  that 
moves  the  receiving  needle;  and  (4)  by  increas- 
ing the  lateral  distance  of  the  sheets.  In  cases 
where  lateral  distance  could  be  got  he  recom- 
mended increasing  it,  as  then  a  smaller  battery 
power  would  suffice.  In  telegraphing  by  this 
method  to  Ireland  or  France  abundance  of  lateral 
distance  could  be  got,  but  for  America  the  lateral 
distance  in  Britain  was  much  less  than  the  dis- 
tance across." 

This  devoted  investigator's  latest  experiment 
with  wireless  telegraphy  took  place  in  1860, 
when  he  again  succeeded  in  strongly  moving  a 
telegraphic  needle  across  the  Tay  at  a  point 
where  it  is  more  than  a  mile  wide.  Two  years 
later  he  died,  perfectly  convinced  to  the  last,  as 
we  are  told,  of  the  correctness  of  his  views  and 
of  the  ultimate  triumph  of  his  method  of  tele- 
graphy. 


CHAPTER  III 

Highton  and  his  suggestions — Other  experimenters  in  Wire- 
less Telegraphy — A  proposal  to  communicate  with 
besieged  Paris  by  telegraphy  through  the  water — 
Its  necessity  obviated  by  the  armistice — Wireless  tele- 
graphy in  India — An  American  dentist's  conception 
and  experiments. 

WHILE  Lindsay  thus  occupied  himself  in 
Britain  Bonelli  was  busy  with  similar  investiga- 
tions in  Italy,  just  as  Gintl  (first  inventor  of 
duplex  telegraph)  was  in  Austria,  and  Bouchot 
and  Donat  in  France.  So  little,  however,  is 
known  about  their  experiments  that  it  must 
suffice  here  simply  to  mention  their  names,  going 
to  show,  as  they  do,  that  the  idea  of  wireless  tele- 
graphy was,  as  we  say,  very  much  "  in  the  air." 

Of  another  investigator,  who  was  at  work  at 
the  same  time,  and  whose  researches,  begun  in 
1852,  extended  over  a  period  of  twenty  years, 
it  is  necessary  to  speak  at  greater  length.  This 
was  Henry  Highton,  who,  basing  his  suggestions 
upon  numberless  experiments  designed  with  the 
view  of  finding  out  the  best  means  of  telegraph- 
ing between  two  places  separated  by  water,  de- 
scribed in  a  paper  on  Telegraphy  without  In- 
sulation, read  before  the  Society  of  Arts  (May 
40 


HIGHTON'S   PLANS.  41 

i,  1872),  three  plans  by  which  that  end  could  be 
attained.  The  first  is  practically  the  same  as  the 
plan  adopted  by  Morse.  In  the  water  near  one 
bank  are  placed  the  copper  plates  A  B  (Fig.  5), 
which  are  connected  by  a  wire,  including  the  bat- 
tery P.  Near  the  opposite  bank  are  submerged 
similar  plates,  C  D,  connected  by  a  wire,  in  the 
circuit  whereof  is  placed  the  galvanometer  G. 
Between  A  and  B 
the  current  will  pass 
by  every  possible 
route,  in  quantities 
inversely  p  r  o  p  o  r  - 
tional  to  their  resist- 
ances ;  parts  passing 
direct  by  A  B,  and 

other  portions  by  A,  C,  D,  B,  and  by  A, 
C,  G,  D,  B.  If  the  plates  be  large,  and  A  C 
and  B  D  respectively  comparatively  near  to 
each  other,  an  appreciable  current  will  pass 
from  A  C,  through  G,  back  to  D  B ;  but  if  the 
plates  be  small,  the  battery  power  small,  and  the 
distance  from  A  to  B,  and  from  C  to  D,  com- 
paratively short,  no  appreciable  amount  will  pass 
through  the  galvanometer  circuit. 

Mr.  Highton  held  that  it  was  possible,  by 
erecting  a  very  thick  line  wire  from  the  Hebrides 
to  Cornwall,  by  the  use  of  enormous  plates  at 
each  extremity,  and  by  an  enormous  amount  of 
battery  power  (as  regards  quantity)  to  transmit 


42    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

a  current  which  would  be  sensibly  perceived  in 
a  similar  line,  with  equally  large  plates,  on  the 
other  side  of  the  Atlantic.  "  But,"  adds  Mr. 
Highton,  "  the  trouble  and  expense  would  prob- 
ably be  much  greater  than  that  of  laying  a  wire 
across  the  ocean." 

Highton's  second  plan  was  to  lay  across  the 
water  two  wires  kept  from  metallic  contact  with 
each  other,  and  to  work  with  that  portion  of  the 
current  which  preferred  to  pass  through  this 
metallic  circuit  instead  of  passing  through  the 
liquid  conductor,  having  currents  of  low  tension 
from  batteries  of  large  surface.  In  certain  cases, 
finally,  this  double  line  across  the  water  might 
be  dispensed  with  and  a  single  imperfectly  in- 
sulated wire  used  in  its  place,  when  the  water 
itself  would  serve  for  the  return  current.  Of 
these  three  plans  Highton  held  the  second  to  be 
the  simplest  and,  on  the  whole,  the  most  work- 
able. It  was,  as  a  matter  of  fact,  the  one  largely 
made  use  of  by  telegraph  engineers  in  India  for 
crossing  large  rivers,  for  which  purpose  it  was 
found  specially  adapted,  provided  the  two  wires 
sunk  in  the  water  were  a  sufficient  distance  from 
each  other. 

There  were  many  other  workers  in  the  same 
field  in  these  mid-nineteenth  century  years,  and 
a  large  number  of  patent  specifications  are  to  be 
seen  at  the  office  for  that  purpose  in  Chancery 
Lane,  London,  in  which  the  subject  of  electric 


FRENCH   EXPERIMENTS.  43 

signaling  is  dealt  with,  chiefly  on  the  lines  laid 
down  by  one  or  other  of  the  investigators  whose 
experiments  have  been  described.  Their  methods 
need  not  be  described ;  but  there  was  one  pro- 
jected plan  of  signaling  which,  both  on  account 
of  its  historical  interest  and  its  striking  origi- 
nality, is  well  worthy  of  a  place  in  these  pages.  I 
refer  to  the  method  proposed  by  M.  Bourbouze, 
a  noted  French  electrician,  for  establishing  tele- 
graphic communications  between  Paris  during 
the  time  it  was  invested  by  the  German  army 
and  the  French  forces  operating  in  the  provinces. 
Bourbouze's  proposal  was,  from  a  suitable  place 
outside  the  German  lines,  to  discharge  a  strong 
current  into  the  river  Seine,  and  to  receive  the 
same,  or  such  portion  of  it  as  could  be  picked  up 
by  a  metal  plate  sunk  in  the  river  and  connected 
with  a  delicate  galvanometer.  Some  prelimi- 
nary experiments  between  the  Hotel  de  Ville  and 
the  works  of  M.  Claparede  at  St.  Denis  having 
proved  successful,  it  was  decided  to  put  the  plan 
in  operation.  With  this  object  in  view  M. 
d'Almeida,  on  December  17,  1870,  quitted  Paris 
by  balloon,  and,  after  some  perilous  experiences, 
descended  outside  the  German  lines,  and  made 
his  way  by  Lyons  and  Bordeaux  to  Havre.  From 
that  place  the  apparatus  necessary  for  the  ex- 
periment were  ordered  from  England,  and  on 
January  14,  1871,  M.  d'Almeida  arrived  at 
Poissy  on  the  Seine,  where  the  contemplated 


44    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

operations  were  to  be  set  in  motion.  Unfor- 
tunately, however,  the  river  was  found  to  be 
frozen  over,  and  so  the  experiment  had  to  be 
postponed  until  January  24.  By  that  time,  how- 
ever, all  need  for  it  had  gone  in  consequence  of 
the  arrangement  of  an  armistice,  which  in  due 
course  was  followed  by  the  treaty  of  peace. 
Some  years  later,  Bourbouze  instituted  some  ex- 
periments by  way  of  testing  his  proposed  method 
of  electric  communication  without  wires,  but  to 
what  extent  they  were  successful,  if  at  all,  does 
not  appear  to  have  been  made  public. 

Although  the  proposed  experiments  of  M. 
Bourbouze,  which  were  based  on  the  same  prin- 
ciple as  those  of  Messrs.  Bering  and  Highton, 
referred  to  above,  came  to  nothing,  yet  it 
was  not  many  years  before  the  methods  which 
they  adopted,  and  worked  at  with  such  indiffer- 
ent results,  were  put  in  operation  with  conspicu- 
ous success  in  India. 

At  a  very  early  date  in  the  annals  of  tele- 
graphy a  great  want  was  felt  in  India  for  some 
form  of  wireless  telegraphy,  in  order  to  carry 
the  electric  current  across  the  many  broad  rivers 
that  exist  in  that  country,  whose  frequent  flood- 
ing and  other  obstacles  caused  telegraphy  by 
cable  to  be  fraught  with  many  difficulties.  A 
large  number  of  experiments,  extending  over 
many  years,  were  made  by  different  gentlemen 
connected  with  the  Indian  Telegraph  Depart- 


EXPERIMENTS   IN   INDIA.  45 

ment,  including  Blisset,  Schwendler,  and  W.  P. 
Johnston,  all  resulting  in  but  indifferent  success, 
until,  in  1889,  Mr.  W.  F.  Melhuish,  continuing 
the  operation  of  his  predecessor,  Mr.  Johnston, 
finally  triumphed  over  the  difficulties  that  had 
baffled  so  many  previous  investigators.  It  is 
needless  to  go  into  the  details  of  his  experiments, 
which  show  the  practical  realization  of  the 
methods  proposed  by  Highton  and  Bering.  He 
made  it  clear  that  "  at  all  river  cable  crossings 
where  the  cables  are  laid  in  separate  alignments 
— the  further  apart  the  better — should  the 
cables  become  interrupted,  communication  may 
still  be  maintained  from  bank  to  bank,  by  using 
vibrating  sounds,  thus  avoiding  the  delay,  incon- 
venience, and  cost  of  a  boat  service." 

Melhuish  adds  that,  in  the  case  of  such  a 
parallel  cable  crossing,  "  besides  the  circuits 
afforded  by  the  copper  conductors,  when  these 
are  in  working  order,  there  is  always  an  addi- 
tional local  circuit  available  by  means  of  the  iron 
guards  between  the  opposite  cable-houses,  and 
that  this  circuit  could  be  used  by  means  of  the 
vibrating  sounder  as  a  talking  circuit,  in  case 
of  necessity,  without  interrupting  through  work- 
ing on  either  of  the  cables." 

This  reference  to  Melhuish's  experiments  in 
India,  has,  however,  carried  us  a  little  too  far 
forward  in  our  story,  and  we  must  go  back  a 
few  years  in  order  to  give  a  few  particulars 


4.6    THE  STORY  OF  WIRELESS  TELEGRAPHY. 

anent  a  scheme  propounded,  and  to  some  extent 
tested,  by  an  American  who  was  much  talked 
about  in  his  day.  This  was  one  Mahlon  Loomis, 
a  dentist,  who  conceived  the  idea  of  utilizing  the 
electricity  known  to  exist  in  the  atmosphere  for 
the  purpose  of  establishing  electrical  communi- 
cations between  distant  places.  In  the  descrip- 
tion of  his  patent,  taken  out  in  1872,  he  speaks 
of  his  discovery  as  a  means  of  turning  natural 
electricity  to  account  for  "  establishing  an  elec- 
trical current  or  circuit  for  telegraphic  or  other 
purposes  without  the  aid  of  wires,  artificial  bat- 
teries, or  cables."  By  this  method  he  hoped  to 
be  able  to  communicate  "  from  one  continent  of 
the  globe  to  another." 

His  plan  was,  to  use  his  own  words,  "  to  seek 
as  high  an  elevation  as  practicable  on  the  tops  of 
high  mountains,  and  thus  establish  electrical 
connection  with  the  atmospheric  stratum  or 
ocean  overlying  local  disturbances."  Upon  these 
mountain-tops  his  plan  was  to  "  erect  suitable 
towers  and  apparatus  to  attract  the  electricity, 
or,  in  other  words,  to  disturb  the  electrical 
equilibrium,  and  thus  obtain  a  current  of  elec- 
tricity, or  shocks  or  pulsations,  which  traverse 
or  disturb  the  positive  electrical  body  of  the 
atmosphere  between  two  given  points  by  connect- 
ing it  to  the  negative  electrical  body  of  the  earth 
below." 

The  notion  may  seem  vague  and  wild;  but  if 


MAHLON   LOOMIS.  47 

we  are  to  believe  the  reports,  Loomis  actually 
tested  his  idea  by  selecting  two  "  mountain- 
tops  "  in  West  Virginia  and  sending  up  kites 
therefrom,  the  strings  of  which  contained  a  fine 
copper  wire.  These  conductors  were  provided 
with  the  necessary  apparatus  for  sending  and 
receiving  messages,  and  though  the  two  stations 
were  ten  miles  apart,  and  the  only  "  electro- 
motor" was  "  the  atmospheric  current  between 
the  kites,"  yet  the  attempt  to  communicate 
between  the  two  summits  was  successful. 

So  successful  indeed  were  these  experiments 
said  to  be  that  there  was  talk  of  a  tower  being 
built  on  one  of  the  loftiest  peaks  of  the  Rocky 
Mountains  to  correspond  with  a  similar  erection 
on  some  suitable  Alpine  summit.  On  the  top  of 
these  towers  a  tall  mast  was  to  be  placed  to  carry 
an  apparatus  for  collecting  electricity.  Nothing 
appears  to  have  come  of  the  project  beyond  a 
good  deal  of  journalistic  talk,  not  unmixed  with 
ridicule ;  but  it  is  interesting  to  note  that  it  is  in 
connection  with  this  scheme  of  Mahlon  Loomis 
that  we  first  hear  of  the  application  of  vertical 
conductors,  or  antennae,  as  they  are  sometimes 
called,  for  the  transmission  of  signals  to  a  great 
distance. 


CHAPTER  IV 

Effect  of  improvements  in  cables — Invention  of  the  tele- 
phone— Researches  of  Professor  Trowbridge  with 
— His  experiments  with  Wireless  Telegraphy — Pro- 
fessor Graham  Bell's  Investigations— Dolbear's  work- 
ing with  etheric  waves — His  anticipation  of  Marconi. 

THE  various  experiments  which  we  have 
hitherto  been  considering  had  for  the  most  part 
their  origin  in  the  great  cost  and  the  technical 
difficulties  involved  in  the  laying  of  completely 
insulated  and  externally  well-protected  cables, 
as  well  as  in  the  obstacles  to  speedy  repair  which 
had  to  be  contended  with  in  case  of  injury. 
When  these  various  difficulties  and  hindrances 
had  in  the  main  been  overcome  by  the  improve- 
ments which  were  gradually  introduced  in  the 
construction  of  submarine  cables,  the  attention 
of  inventors  and  investigators  became  for  the 
time  being  directed  from  wireless  telegraphy  to 
other  problems  connected  with  electric  communi- 
cation, and  not  without  success. 

One  of  the  triumphs  of  research  that  signal- 
ized the  interval  between  the  project  last  referred 
to  and  the  one  next  in  importance,  connected 
48 


INVENTION   OF  THE  TELEPHONE.          49 

with  telegraphy  without  wires,  was  the  introduc- 
tion of  the  telephone.  This  wonderful  little  in- 
strument, the  invention  of  Professor  A.  Graham 
Bell,  was  given  to  the  world  in  1876,  and  soon 
became,  in  a  most  accidental  way,  a  potent  means 
of  advancing  the  study  of  electric  communica- 
tion without  continuous  wires.  It  was  found 
almost  from  the  first  that  the  telephone  was  so 
sensitive  that  sounds  being  transmitted  on  ad- 
jacent lines  could  be  heard  in  it.  Various  ex- 
periments were  made  to  test  this  property  of  the 
telephone,  among  others  by  Edison,  Prof.  E. 
Sacher,  of  Vienna,  M.  Henri  Dufour,  and  others. 
Professor  Trowbridge,  of  Harvard  Univer- 
sity, however,  was  the  first  to  put  the  possibili- 
ties here  indicated  to  the  test  of  systematic  ex- 
periments. Utilizing  the  wire  which  runs  from 
the  Observatory  to  Boston  for  the  purpose  of 
sending  time  signals,  he  was  successful  in  obtain- 
ing the  transference  of  these  signals  to  another 
wire  from  150  to  180  meters  in  length,  which 
was  something  like  1,600  meters  distant  from 
the  first.  Trowbridge  varied  his  experiments  in 
many  ways,  and  as  the  result  came  to  the  con- 
clusion ( i )  "  that  a  battery  terminal  discharging 
electricity  to  the  earth  is  the  center  of  waves  of 
electrical  energy,  ever  widening,  and  ever  de- 
creasing in  strength  or  potential  as  they  widen ; 
and  (2)  that,  on  tapping  the  earth  by  means  of 
a  wire  at  two  points  of  different  potentials  (not 
4 


50     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

very  distant  if  near  the  central  source,  but  more 
removed  the  farther  from  that  source)  we  can 
obtain  in  the  telephone  evidence  of  their  exist- 
ence." 

Professor  Trowbridge  goes  on  to  say,  quoting 
Steinheil's  dictum :  "  The  spreading  of  the  gal- 
vanic effect  is  proportional  ...  to  the  square 
of  the  distance,  so  that  at  the  distance  of  fifty 
feet,  only  exceedingly  small  effects  can  be  pro- 
duced. Had  we  the  means  which  could  stand 
in  the  same  relation  to  electricity  that  the  eye 
stands  to  light,  nothing  would  prevent  us  from 
telegraphing  through  the  earth  without  conduct- 
ing wires."  Trowbridge  adds  that  the  telephone, 
though  far  from  fulfilling  the  conditions  re- 
quired by  Steinheil,  is  the  nearest  approach 
thereto,  and  then  proceeds : 

"  The  theoretical  possibility  of  telegraphing 
across  the  Atlantic  without  a  cable  is  evident 
from  the  survey  which  I  have  undertaken.  The 
practical  possibility  is  another  question.  Power- 
ful dynamo-electric  machines  could  be  placed  at 
some  point  in  Nova  Scotia,  having  one  end  of 
their  circuit  grounded  near  them  and  the  other 
end  grounded  in  Florida,  the  connecting  wire 
being  of  great  conductivity  and  carefully  in- 
sulated throughout.  By  exploring  the  coast  of 
France,  two  points  on  surface  lines  not  at  the 
same  potential  could  be  found ;  and  by  means 
of  a  telephone  of  low  resistance,  Morse  signals 


PROFESSOR  TROWBRIDGE.  51 

sent  from  Nova  Scotia  to  Florida  could  be  heard 
in  France." 

Professor  Trowbridge  adds  that  "  theoretic- 
ally, this  is  possible,  but  practically,  with  the 
light  of  our  present  knowledge,  the  expenditure 
of  energy  on  the  dynamo-electric  machines 
would  be  enormous." 

But  although  Trowbridge  perceived  that  this 
difficulty  would  prevent  his  method  from  being 
utilized  for  transocean  telegraphy,  he  thought 
it  might  be  turned  to  account  for  the  intercom- 
munication of  ships  at  sea.  He  devoted  a  great 
deal  of  thought  to  this  subject,  and  suggested 
two  plans  by  which  ships  at  sea  might  be  enabled 
to  speak  with  each  other.  They  do  not  differ 
very  materially  the  one  from  the  other.  In  each 
case  the  ships  must  be  provided  with  a  powerful 
dynamo,  one  terminal  of  the  dynamo  connecting 
with  the  water  at  the  bow  of  the  vessels,  and  the 
other  to  a  long  wire,  insulated  except  at  its  ex- 
treme end,  trailing  over  the  stern,  and  buoyed 
so  as  not  to  sink.  The  current  from  the  dynamo 
would  by  this  means  spread  out  over  the  water 
and,  so  to  speak,  saturate  it  with  electricity.  The 
idea  is  that  an  approaching  vessel,  suitably  pro- 
vided with  a  telephone,  the  ends  of  whose  wires 
passed  over  the  bow  and  stern  respectively, 
would  thus  be  able  to  pick  up  any  sounds  issuing 
from  the  dynamo  of  the  first  vessel,  and  so  get 
into  communication. 


52     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

Professor  Trowbridge's  second  plan  was  to 
use,  in  place  of  a  telephone  circuit,  a  sensitive 
galvanometer  connected  with  a  cross  arm  of 
wire,  whose  ends  should  dip  into  the  sea  on  either 
side  of  the  vessel.  As  in  the  first-named  method, 
the  water  would  be  saturated  with  electricity, 
and  when  another  vessel  came  within  this  area 
the  galvanometer  would  show  how  the  equipo- 
tential  lines  were  disturbed,  and  if  a  map  of  those 
lines  were  carefully  traced  the  position  of  the 
approaching  ship  could  be  fixed.  The  idea  of 
this  second  method  is,  of  course,  to  prevent  colli- 
sions in  times  of  darkness  and  fog,  and  Trow- 
bridge  throws  out  the  further  suggestion  that  it 
might  be  applied  to  saturating  the  water  about 
a  rock,  so  that  a  ship  might  take  electrical  sound- 
ings and  ascertain  its  position  from  electrical 
maps  carefully  made  out. 

Another  ingenious  method  devised  by  Pro- 
fessor Trowbridge  for  obviating  collisions  during 
fog  is  shown  in  the  annexed  diagram  (Fig.  6), 
in  which  M  is  a  microphonic  contact  in  a  water- 
tight box.  The  face  A  of  the  box  constitutes  a 
vibrating  diaphragm,  the  vibrations  of  which 
are  conveyed  to  the  microphonic  contact  M.  The 
wires  from  the  microphone  M  are  conveyed  to 
a  battery  B,  and  then  through  the  primary  coil 
P  of  an  induction  coil.  In  the  circuit  of  the  lat- 
ter is  placed  a  telephone.  The  water-tight  box 
was  lowered  into  the  water  from  the  side  of  a 


AERIAL  TELEGRAPHY.  53 

boat.  An  assistant  stationed  on  land  made 
sounds  under  water  by  striking  two  stones 
together,  and  by  various  other  means,  while 
Trowbridge  listened  at  the  telephone  from  a 
point  up  the  stream. 
When  distant  three  or 
four  hundred  feet  or 
more,  the  sounds  were 
transmitted  through  ^  FIG.  6. 

the  water  to  the  tele- 
phone, and  similar  results  were  obtained  when 
the  sounds  were  made  from  another  boat.  With 
more  powerful  sources  of  sound,  such  as  the 
noise  produced  by  steam  condensing  in  a  pipe 
under  water,  signals  were  transmitted  more  than 
a  mile  under  water. 

These  investigations  occupied  Professor  Trow- 
bridge between  the  years  1880  and  1884.  Sub- 
sequent to  this  he  gave  considerable  attention 
to  the  question  of  aerial  telegraphy,  in  these  re- 
searches also  having  in  view  the  practicability 
of  establishing  communications  between  ship  and 
ship.  He  was  led  to  the  conclusion  that  electro- 
magnetic conduction  would  best  serve  this  pur- 
pose, and  devised  a  means  whereby  such  process 
could  be  utilized.  His  apparatus  consisted  of 
two  coils  of  copper  wire  of  many  convolutions, 
the  ends  of  one  whereof  were  attached  to  a  tele- 
phone, while  the  other  was  connected  with  a 
battery  through  a  key.  If  these  were  placed 


54     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

parallel  to  each  other,  and  within  a  few  feet 
apart,  each  time  the  current  was  made  and  broken 
in  the  battery  coil,  instantaneous  currents  were 
produced  by  induction  in  the  coil  attached  to  the 
telephone,  as  was  attested  by  the  clicks  of  the 
latter. 

Making  use  of  this  principle,  Professor  Trow- 
bridge  proposed  to  stretch  a  wire  ten  or  twelve 
times  to  and  fro,  from  the  yard-arms  of  a  vessel's 
foremast,  and  connect  it  at  the  two  ends  with  a 
powerful  dynamo  or  battery,  or  with  a  tele- 
phone. When  another  vessel  similarly  provided 
approached  the  first,  if  the  current  on  one  of 
them  were  interrupted  a  great  many  times  per 
second,  a  musical  note  would  be  heard  in  the 
telephone  on  the  other.  The  sound  would  be 
strongest  when  the  two  coils  were  parallel 
the  one  to  the  other.  If  therefore  the  coils 
were  movable,  the  position  of  greatest  effect 
could  soon  be  found,  and  so  the  direction  in 
which  the  vessel  was  approaching  be  ascer- 
tained. 

The  method  seems  very  simple,  but  for  practi- 
cal application  the  difficulties  appear  too  great. 
To  produce  an  audible  note  at  the  distance  of 
half  a  mile  would  require  a  coil  of  wire  or  a 
strength  of  current  beyond  what  was  feasible. 
Such  was  Professor  Trowbridge's  conclusion, 
and,  though  others  have  worked  in  the  same  line 
of  investigation,  including  Professor  Henry  and 


TRIALS  THROUGH  WATER.  55 

Sir  J.  Oliver  Lodge,  the  problem  remains  much 
as  Trowbridge  left  it. 

These  investigations  marked  the  beginning  of 
a  fresh  attack  upon  the  problem  of  wireless  tele- 
graphy, and  were,  during  the  next  few  years, 
followed  by  some  remarkable  achievements  on 
the  part  of  a  number  of  workers  in  electrical 
science.  The  first  in  point  of  time  was  Prof. 
Graham  Bell,  who,  basing  his  investigations  on 
some  experiments  made  with  the  galvanometer 
by  Professor  Adams,  of  King's  College,  turned 
the  telephone  to  account  in  tracing  equipotential 
lines  and  surfaces.  The  results  of  these  experi- 
ments he  communicated  to  the  American  As- 
sociation for  the  Advancement  of  Science  in 
1884,  and  they  are  of  so  interesting  a  nature  as 
to  be  worth  quoting  somewhat  in  extenso. 

"  In  a  vessel  of  water,"  he  writes,  "  I  placed  a 
sheet  of  paper.  At  two  points  on  that  paper 
were  fastened  two  ordinary  sewing-needles, 
which  were  also  connected  with  an  interrupter 
that  interrupted  the  circuit  about  one  hundred 
times  a  second.  Then  I  had  two  needles  con- 
nected with  a  telephone :  one  needle  I  fastened 
on  the  paper  in  the  water  and  the  moment  I 
placed  the  other  needle  in  the  water,  I  heard  a 
musical  sound  from  the  telephone.  By  mov- 
ing this  needle  around  in  the  water,  I  would 
strike  a  place  where  there  would  be  no  sound 
heard.  This  would  be  where  the  electric  ten- 


56     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

sion  was  the  same  as  in  the  needle,  and  by 
experimenting  in  the  water  you  could  trace  out 
with  perfect  ease  an  equipotential  line  around 
one  of  the  poles  in  the  water." 

Professor  Bell  goes  on  to  say,  respecting  this 
experiment,  that  what  was  true  on  a  small  must 
also  be  true  on  a  large  scale,  and  that  in  this 
method  a  means  might  be  found  of  communicat- 
ing electrical  signals  between  vessels  at  sea.  He 
accordingly  made  some  preliminary  experiments 
in  England,  and  succeeded  in  sending  signals  in 
this  way  across  the  river  Thames.  Then,  urged 
by  Professor  Trowbridge,  he  made  some  further 
experiments,  deriving  therefrom  some  very  valu- 
able results.  The  first  was  on  the  Potomac 
River,  and  he  thus  describes  it : 

"  I  had  two  boats.  In  one  boat  we  had  a 
Leclanche  battery  of  six  elements,  and  an  inter- 
rupter for  interrupting  the  current  very  rapidly. 
Over  the  bow  of  the  boat  we  made  water  con- 
nection by  a  metallic  plate,  and  behind  the  boat 
we  trailed  an  insulated  wire,  with  a  float  at  the 
end  carrying  a  metallic  plate,  so  as  to  bring  these 
two  terminals  about  one  hundred  feet  apart.  I 
then  took  another  boat  and  sailed  off.  In  this 
boat  we  had  the  same  arrangement,  but  with 
a  telephone  in  the  circuit.  In  the  first  boat, 
which  was  moored,  I  kept  a  man  making  signals ; 
and  when  my  boat  was  near  his  I  could  hear 
those  signals  very  well — a  musical  tone,  some- 


TRIALS  THROUGH  WATER.  57 

thing  of  this  kind :  turn,  turn,  turn.  I  then 
rowed  my  boat  down  the  river,  and  at  a  distance 
of  a  mile  and  a  quarter,  which  was  the  farthest 
distance  I  tried,  I  could  still  distinguish  those 
signals. 

"  It  is  therefore  perfectly  practicable  for 
steam-vessels  with  dynamo  machines  ...  to 
know  of  each  other's  presence  in  a  fog  when 
they  come,  say,  within  a  couple  of  miles  of  one 
another,  or,  perhaps,  at  a  still  greater  distance. 
I  tried  the  experiment  a  short  time  ago  in  salt 
water  of  about  twenty  fathoms  in  depth.  I  used 
then  two  sailing  boats,  and  did  not  get  so  great 
a  distance  as  on  the  Potomac.  The  distance, 
which  we  estimated  by  the  eye,  seemed  to  be 
about  half  a  mile ;  but  on  the  Potomac  we  took 
the  distance  accurately  on  the  shore." 

Bell  was  so  confident  of  the  practicability  of 
his  method  that  he  expressed  a  strong  hope  that 
steamships  which  had  dynamo-engines  and  were 
electrically  lighted  would  try  it.  The  idea  was 
that  one  of  them  should  trail  a  mile-long  wire 
electrically  charged  from  the  dynamo,  and  that 
the  end  on  board  should  be  attached  to  a  tele- 
phone. The  telephone  or  dynamo  end  would  be 
positive,  and  the  end  trailing  in  the  water  nega- 
tive. All  the  water  next  the  ship,  within  a  circle 
whose  radius  is  one-half  of  the  length  of  the 
wire  would  be  positive,  while  the  water  within 
the  same  radius  of  the  other  or  negative  end  of 


58     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

the  wire  would  be  negative.  Such  being  the 
case,  it  would  be  impossible  to  approach  within 
the  radius  of  water  so  charged  without  the  tele- 
phone making  the  fact  known.  If  the  ship  so 
approaching  were  provided  with  a  similar  ap- 
paratus the  two  could  communicate  with  each 
other  by  means  of  their  telephones,  and  in  case 
of  fog  would  be  able  to  keep  out  of  each  other's 
way. 

Still  another  American,  Professor  Dolbear  of 
Tuft's  College,  Massachusetts,  was  about  the 
same  time  (1882)  experimenting  on  lines  similar 
to  those  which,  as  we  have  seen,  had  been 
occupying  the  attention  of  Trowbridge  and 
Graham  Bell,  and  so  far  did  he  push  his  re- 
searches that  his  friends  claimed  for  him  priority 
in  the  discovery  of  aerial  telegraphy.  He  did 
actually  send  signals  through  space  without 
wires,  and  came  very  near  the  achievement  which 
is  now  so  indelibly  associated  with  the  name  of 
Marconi.  In  the  early  days  of  his  investigation 
Dolbear  put  the  distance  at  which  he  could  make 
his  sounds  heard  at  half  a  mile,  but  later  it  was 
affirmed  that  he  had  obtained  results  as  far  as 
thirteen  miles  away. 

There  are  some  striking  resemblances  between 
his  method  and  that  of  Marconi,  and  one  can 
hardly  doubt  that,  had  Hertz  then  made  his  great 
discovery  of  the  electric  waves  that  bear  his  name 
Dolbear  might  have  forestalled  his  younger  rival. 


PROFESSOR  DOLBEAR.  59 

Professor  Dolbear  read  a  paper  descriptive  of  his 
method  before  the  American  Association  for  the 
Advancement  of  Science  in  the  month  of  August, 
1882,  in  which  year  he  patented  his  apparatus  in 
the  United  States.  Fig  7  represents  that  appara- 
tus, the  left  being  the  transmitting  and  the  right 


FIG.  7. 

the  receiving  circuit.  The  induction  coil  J  con- 
sists of  a  series  of  turns  of  wire  which  connect 
the  primary  and  secondary  coils.  One  twist  of 
the  coil  is  cut,  and  the  four  ends  of  the  coil  thus 
obtained  are  connected  with  the  battery  B,  with 
the  microphone  transmitter  M,  with  one  end  of 
the  condenser  C,  and  the  earth.  The  battery 
consists  of  a  large  number  of  cells  arranged  in 
series  in  order  to  get  between  the  condenser  C 
and  the  earth  a  potential  difference  of  at  least 
loo  volts. 

In  the  receiving  circuit  is  a  telephone  T, 
which  is  connected  with  the  earth,  E1,  and 
one  end  of  the  condenser,  C1.  The  other  end  of 
the  condenser,  C1,  is  connected  with  one  pole  of 


60    THE   STORY   OF   WIRELESS   TELEGRAPHY. 

the  battery,  B1,  and  through  this  with  one  end 
of  the  condenser,  C2.  This  arrangement  is 
designed  to  charge  the  earth  at  E1,  with  the 
opposing  potential  as  at  E.  As,  however,  the 
condensers,  C1,  C2,  possess  only  a  small  capacity 
their  influence  is  an  inconsiderable  one,  and 
they  were  considered  by  the  inventor  as  not 
essential. 

Fig.  8  represents  in  a  simpler  form  what  takes 
place  when  the  resistance  of  the  microphone  M 


1 

& 


FIG.  8. 


is  subjected  to  changes  by  rapid  vibrations  of  its 
membrane.  J  stands  again  for  the  induction 
coil,  while  C  C1  represent  the  ends  of  con- 
denser of  small  capacity.  Since,  however,  these 
condenser  plates  are  near  to  earth  they  each 
represent  a  second  complete  condenser,  the  earth 
itself  forming  the  second  side.  The  capacity  of 
these  condensers  is  essentially  greater  than  the 
capacity  of  the  condenser  C  C1,  because  the 
capacity  of  a  condenser  stands  in  reverse  re- 


DOLBEAR'S   APPARATUS.  6 1 

lation  to  the  distance  of  the  plates,  and  the  dis- 
tance between  C  and  C1  respectively  and  the  earth 
is  essentially  less  than  the  distance  between  C 
and  C1.  If  we  consider  the  circuit  E  J  B  M  J 
C  C1  T  B1  E1  E,  in  which  a  changeable  electro- 
magnetic current  is  generated  through  the  vibra- 
tions of  M,  it  will  be  seen  that  there  are  figura- 
tively two  currents.  The  one  begins  at  B,  passes 
over  the  transmitter  M,  through  the  coil  J  to  C, 
and  so  to  the  earth  and  thence  over  the  second 
coil  from  J  back  to  B.  The  second  circuit  runs 
in  like  manner,  starting  from  B,  over  M,  in  the 
first  coil  from  J  C  C1  T  B1  E1  E  through  the 
second  coil  from  J  back  to  B.  This  latter  circuit 
serves  for  the  transmission  of  the  signals  pro- 
ceeding from  the  sender  M  to  the  receiver  T.  If 
the  resistance,  the  self-induction,  and  the  capacity 
of  one  of  each  of  these  currents  are  known,  and 
likewise  the  total  output  of  E  M  F  through  the 
battery  and  the  variation  in  resistance  from  M 
be  known,  the  strength  of  the  current  in  each 
of  the  circuits  can  be  reckoned.  It  is  evident, 
however,  that  only  a  very  small  part  of  the  cur- 
rent circulating  in  the  circuit  B  C  E  B  can  be 
of  any  effect.  The  battery  B1,  connected  in 
series  with  B,  increases  the  total  E  M  F  in 
the  whole  circuit  and  hence  a  change  in  re- 
sistance M  will  strengthen  the  current  which 
goes  through  T. 

Dolbear  says  that  he  obtained  his  first  results 


62     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

from  this  apparatus  with  a  large  magneto-elec- 
tric machine  with  one  terminal  grounded  through 
a  Morse  key,  the  other  terminal  being  out  in 
free  air,  and  only  a  foot  or  two  long.  The  re- 
ceiver had  one  terminal  grounded ;  the  other 
was  held  in  the  hand,  his  body  being  insulated, 
and  the  distance  between  grounds  being  about 
sixty  feet.  Louder  and  better  effects  were 
obtained  by  using  an  induction  coil  having  an 
automatic  break,  and  with  a  Morse  key  in  the 
primary  circuit,  one  terminal  of  the  secondary 
grounded,  the  other  in  free  air,  or  in  a  condenser 
of  considerable  capacity,  the  other  having  an  air 
discharge  at  its  opposite  terminal.  At  times  a 
gilt  kite  was  employed  carrying  a  fine  wire  from 
the  secondary  coil.  The  discharges  were  then 
nearly  as  strong  as  if  there  was  an  ordinary 
circuit. 

"  Some  very  interesting  results,"  says  Dolbear, 
"  were  obtained  when  the  static  receiver  with  one 
terminal  was  employed.  A  person  standing  upon 
the  ground  at  a  distance  from  the  discharging 
point  could  hear  nothing;  but  very  little  stand- 
ing upon  ordinary  stones,  as  granite  blocks  or 
steps ;  but  standing  on  asphalt  concrete,  the 
sounds  were  loud  enough  to  hear  with  the  tele- 
phone at  some  distance  from  the  ear.  By 
grounding  the  one  terminal  of  the  induction 
coil  to  the  gas  or  water  pipes,  leaving  the  other 
end  free,  telegraph  signals  could  be  heard  in  any 


SIGNALING   WITHOUT  WIRES.  63 

part  of  a  big  building-  and  its  neighborhood 
without  any  connection  whatever,  provided  the 
person  be  well  insulated." 

At  the  Electrical  Exhibition  held  in  Philadel- 
phia in  1884,  Dolbear  exhibited  an  arrangement 
for  wireless  signaling  which  had  been  effective 
over  limited  distances.  He  used  an  induction 
coil  as  generator  and  a  telephone  as  receiver. 
By  connecting  one  terminal  of  the  secondary 
of  the  induction  coil  to  earth,  and  the  other  to 
one  side  of  a  condenser,  the  other  terminal  where- 
of had  points  for  "  discharging  into  the  air,"  a 
telephone  transmitter  or  Morse  key,  operating 
the  primary  circuit  of  the  induction  coil  with  a 
powerful  battery,  produced  audible  sounds  in  a 
telephone  receiver  one  hundred  feet  away.  One 
terminal  of  the  telephone  was  connected  to  earth, 
the  other  through  a  battery  to  condensers  ar- 
ranged as  at  the  transmitting  end.  Dolbear's 
idea  was  apparently  the  electrification  of  the 
two  "  ground  "  wires  and  the  changing  of  their 
potential  from  positive  to  negative  whenever  a 
signal  was  transmitted.  It  was  an  original  con- 
ception of  the  highest  order,  and  in  one  feature 
furnished  in  advance  a  main  requisite  for  long- 
distance telegraphy,  that  is,  the  vertical  wire. 
There  was  a  distinct  approach,  too,  toward  Mar- 
coni's method  in  the  employment  of  condensers 
and  the  flying  of  gilt  kites  carrying  a  fine  wire. 
Dolbear  showed  also  that  he  was  groping  his 


64     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

way  toward  the  real  thing  in  attributing  some  of 
his  results  to  the  action  of  the  ether. 

That,  however,  is  an  entity  which  at  the  time 
referred  to  was  little  understood,  and  some  of  the 
most  advanced  minds  as  regards  electrical  science 
were  inclined  to  attribute  Dolbear's  singular  re- 
sults as  due  to  "  an  exceptional  application  of 
the  principles  of  electro-static  induction."  There 
can  be  no  doubt  that  Dolbear  was  working  with 
Hertzian  waves,  although  he  did  not  know  it, 
six  years  having  still  to  elapse  before  their  ex- 
istence was  discovered,  and  to  that  extent  there- 
fore he  was  anticipating  Marconi. 


CHAPTER  V 

Telegraphic  communication  with  trains — A.  C.  Brown's 
method — Willoughby  Smith  and  Phelps's  sugges- 
tions— Successful  application  of  the  principle  by 
Edison  and  Gilliland — Edison's  method  applied  to 
ships — Sir  William  Preece's  researches — His  experi- 
ments on  the  Solent — Across  the  Severn — At  Porth- 
cawl— On  the  Bristol  Channel— Loch  Ness— The 
Island  of  Mull — His  theory  of  the  part  played  by  the 
earth  in  electro-magnetic  operations. 

LIKE  Trowbridge  and  Graham  Bell,  Professor 
Dolbear  saw  in  his  aerial  method  a  valuable 
means  of  communication  between  vessels  at  sea. 
This  idea  and  the  cognate  one  of  communication 
with  trains  in  motion  have  been  favorite  subjects 
for  investigation  by  scientific  electricians  since  the 
earliest  days  of  telegraphy.  Many  suggestions 
were  thrown  out,  and  a  large  number  of  ex- 
periments made,  with  a  view  to  establishing  such 
a  system  of  communication  with  traveling 
trains ;  but  as  they  were  based  on  the  principles 
of  ordinary  telegraphy  they  do  not  concern  us 
here. 

The  first  person  to  suggest  an  advance  upon 
this  method  appears  to  have  been  Mr.  A.  C. 
Brown,  who,  in  a  letter  published  in  the  Elec- 
5  65 


66    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

trician  for  March  21,  1885,  says  that  four  years 
earlier  (1881)  he  laid  before  the  Managing 
Director  of  the  United  Telephone  Company  a 
paper  in  which  he  set  forth  a  scheme  by  which 
signalmen  might  communicate  directly  with  the 
guards  or  drivers  of  trains.  He  proposed  to 
run  a  wire  along  the  permanent  way,  parallel 
with  the  rails,  and  to  wind  a  coil  of  wire  round 
the  engine  or  carriage  to  be  communicated  with, 
in  such  a  way  as  to  get  as  long  a  stretch  of  wire 
parallel  to,  and  as  near  to  the  line  wire  as 
possible,  so  as  to  be  well  exposed  to  the  in- 
ductive action  thereof.  He  then  proposed  to 
place  in  the  signal  boxes  a  battery,  signaling 
key,  and  rapid  make-and-break  instrument,  or 
buzzer,  and  to  signal  thereby  to  the  train,  using  a 
telephone  in  circuit  with  the  train-coil  as  a 
receiver. 

A  similar  suggestion  was  thrown  out  by  Mr. 
Willoughby  Smith  in  a  paper  read  before  the 
Institution  of  Electrical  Engineers  in  November 
1883,  in  which  he  says  that  one  or  more  spirals 
might  be  fixed  between  the  rails  at  any  con- 
venient distance  from  the  signaling  station,  so 
that,  when  necessary,  intermittent  currents  could 
be  sent  through  the  spirals.  Another  spiral  could 
be  fixed  beneath  the  engine,  or  guard's  van,  and 
connected  to  one  or  more  telephones  placed  near 
those  in  charge  of  the  train.  Then,  as  the  train 
passed  over  the  fixed  spiral,  the  sound  given  out 


COMMUNICATION   WITH   TRAINS.  67 

by  the  transmitter  would  be  loudly  reproduced 
by  the  telephone,  and  indicate  by  its  character 
the  signal  intended. 

Phelps.  another  experimenter  in  the  same  line, 
worked  out  a  system  which  was  a  further  de- 
velopment of  that  of  Willoughby  Smith.  Along 
the  whole  length  of  railway  line,  between  the 
rails,  he  proposed  to  lay  an  insulated  wire,  which 
was  connected  at  the  stations  with  sending  and 
receiving  apparatus.  Beneath  the  guard's  van  or 
other  carriage  were  several  coils  of  wire,  whose 
ends  were  connected  with  similar  apparatus  in 
the  van  or  carriage.  The  sending  apparatus 
consisted  of,  in  addition  to  a  battery  and  a  key, 
an  automatic  interrupter,  which  was  put  in  action 
the  instant  the  key  was  depressed.  From  this 
resulted  an  intermittent  stream  of  sounds  which 
awoke  a  similar  current  of  induced  sounds  in  the 
coil  beneath  the  train.  The  tympanum  of  the 
telephone,  which,  as  the  receiving  instrument  was 
connected  with  the  end  of  the  coil,  would  be  set 
in  motion  by  this  current  and  so  make  known 
what  was  required.  Or,  in  place  of  the  telephone, 
a  suitable  relay  might  be  added  and  in  connection 
therewith  an  apparatus  for  giving  the  Morse 
alphabet,  whereby  communications  could  be  sent 
to  and  from  the  transmitting  stations. 

In  1885  a  further  development  of  the  principle 
herein  set  forth  was  patented  by  Edison  and 
Gilliland.  In  their  specification  the  invention  is 


68     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

described  as  "  an  apparatus  for  telegraphing  be- 
tween moving  trains,  or  between  trains  and  sta- 
tions, by  induction,  and  without  the  use  of  con- 
necting wires."  The  chief  difference — although 
there  are  other  important  ones — consists  in  the 
fact  that  Edison  and  Gilliland  made  use  of  the 
ordinary  telegraph  wires  running  along  the  side 
of  the  railway  in  place  of  a  wire  specially  laid 
between  the  lines.  The  details  of  a  transmitting 
installation  as  arranged  on  a  train  is  shown  in 
Fig.  9.  It  consists  of  an  induction  apparatus, 
whose  primary  circuit,  besides  a  battery  and  a 
Morse  key,  contains  also  an  automatic  current- 
breaker.  The  terminal  of  the  second  wire  is 
carried  to  earth  by  means  of  the  wheels  of  the 
train  and  the  rails  on  which  they  run,  while  the 
other  terminal  conducts  to  a  metallic  condensing 
surface,  properly  insulated,  which  is  stretched 
along  the  top  or  side  of  the  car.  This  arrange- 
ment was  later  replaced  by  the  metal  roof  of  the 
car.  When  the  Morse  sounder  in  the  primary 
circuit  of  the  induction  apparatus  is  depressed, 
and  by  this  means  the  instrument  is  put  in  action, 
the  secondary  wires  connected  with  the  metallic 
condensing  surface  receive  static  impulses.  These 
act  inductively  upon  the  telegraph  wires,  which 
receive  and  convey  exactly  equivalent  impulses. 
These  in  turn  affect  the  condensing  surface  upon 
the  carriages  of  the  other  train,  and  cause  im- 
pulses which  are  audible  in  the  telephone. 


EDISON   AND    GILLILAND. 


69 


Trains  might  likewise  be  supplied  with  receiv- 
ing apparatus ;  and  in  order  that  it  might  be 
possible  to  telegraph  thereto  from  a  station, 
Edison  and  Gilliland  erected  between  the  tele- 
graph wires  a  large  metallic  condensing  surface 


FIG.  9. 

connected  with  the  station  by  a  wire.  The  sta- 
tions being  thus  connected  inductively  with  the 
line  wires,  the  same  as  the  trains,  signals  could 
be  received  and  transmitted  by  a  station  just  as 
by  a  train,  signals  being  sent  by  keys,  circuit 
breakers,  and  induction  coils,  and  received  by 
telephones. 


70     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

This  system  of  train  telegraphy  was  put  in 
practical  operation  on  the  Lehigh  Valley  Rail- 
road in  1887,  and  proved,  so  far  as  actual  work- 
ing was  concerned,  an  undoubted  success ;  but 
from  a  business  point  of  view  it  turned  out  a 
failure.  It  had  been  thought  that  the  traveling 
public  would  find  it  a  great  boon,  and  that  mes- 
sages to  and  from  trains  would  be  constantly 
flashing  hither  and  thither.  Such,  however,  was 
not  found  to  be  the  case,  and  in  a  few  months 
"  train  telegraphy "  of  this  description  was  a 
thing  of  the  past.  Somewhat  later  Mr.  Edison 
took  out  a  fresh  patent  for  the  application  of 
his  method  of  aerial  telegraphy  on  a  scale  that 
would  adapt  it  for  communication  between  ves- 
sels at  sea,  or  between  ships  at  sea  and  stations 
on  land. 

The  apparatus  he  devised  for  the  purpose  is 
shown  in  Fig  10.  In  C  C1,  elevated  a  consider- 
able distance  above  the  ground,  we  have  two 
capacity  surfaces  which  are  connected  by  wire 
with  the  receiver  and  with  the  secondary  coil  of 
the  induction  apparatus.  The  receiving  appar- 
atus, called  the  "  Electromotograph,"  consists  of 
a  rotating  chalk  cylinder,  whereto  is  applied  a 
metal  brush,  which  through  the  resulting  friction 
gives  forth  a  sound  of  a  certain  height.  By  the 
passage  of  the  electrical  current  over  the  brush 
through  the  chalk  cylinder  the  strength  of  the 
position  is  altered,  and  a  sound  oi  a  different 


THE  ELECTROMOTOGRAPH. 


71 

of    sound 


quality    is    generated.     This    change 
serves  to  distinguish  the  signals. 

In  the  place  of  this  receiver  (represented  in 
the  diagram  by  R)  any  receiving  apparatus  de- 
pending on  alternating  currents  may  be  employed, 
a  rotating  current-breaker  U  or  U1,  closed  re- 
spectively by  the  key  T  or  T1,  is  connected  with 


FIG.  10. 

the  primary  coil  of  the  inductive  apparatus.  If 
the  key  be  put  down  there  ensues  in  the  primary 
coil  a  series  of  rapidly  successive  current  im- 
pulses, and  corresponding  alternating  currents 
are  called  forth  in  the  secondary  coil,  which 
spread  over  the  surface  of  the  elevated  conden- 
sers, whereby  the  condensers  are  charged,  dis- 
charged, in  the  opposing  sense  charged,  and 


72     THE   STORY   OF  WIRELESS  TELEGRAPHY. 

These  electrostatic  impulses  are  now  trans- 
ferred by  way  of  the  static  induction  to  the  con- 
densers of  the  receiver  and  make  themselves  felt 
in  the  receiving  apparatus  itself.  The  air  lying 
between  the  condensing  plates  forms  the  dielec- 
tric of  the  condensers  thus  created,  and  we  have 
again  the  case  of  a  circuit  which  contains  resist- 
ance, self-induction,  and  capacity  in  series,  and 
by  which  the  alternating  current  is  generated  by 
a  succession  of  impulses  of  relatively  lower  fre- 
quency. 

In  this  patent  Edison  is  shown  to  be  the  first 
who  recognized  the  advantage  of  an  elevated 
condenser.  He  foresaw  the  difficulties  that 
would  arise  to  the  employment  of  his  method 
between  distant  points  on  land,  from  the  induc- 
tive absorbing  effects  of  houses,  trees,  and  hills. 
As  a  means  of  overcoming  these  impediments, 
he  suggested  increasing  the  height — "  by  using 
very  high  poles  or  captive  balloons" — from 
which  the  signaling  operations  should  be  con- 
ducted. In  these  "  high  poles  and  captive  bal- 
loons "  we  have,  of  course,  another  anticipation 
of  Marconi,  with  his  tall  masts  set  on  houses  and 
high  places. 

We  have  seen  how  the  experiments  of  Pro- 
fessor Trowbridge  set  a  number  of  experiment- 
ers to  work,  and  with  what  results.  But  there 
was  still  another  inspired  by  his  researches, 
whom  we  have  not  yet  mentioned,  and  whose 


SIR   WILLIAM   H.   PREECE.  73 

investigations  were  of  the  highest  importance.  I 
refer  to  Sir  (then  Mr.)  William  H.  Preece,  for 
many  years  engineer-in-chief  to  the  British  Post- 
al Telegraph  Department.  Sir  William  had  his 
attention  drawn  to  the  subject  of  wireless  tele- 
graphy very  early  in  his  professional  career,  hav- 
ing been  witness  of  an  experiment  made  by  Lind- 
say at  the  York  Road  Stores  of  the  Electric 
Telegraphy  Company,  London,  in  1854.  His 
own  personal  investigations,  however,  date  from 
1882,  when  (in  the  month  of  March)  he  tested 
the  possibility  of  telegraphing  without  connect- 
ing wires  across  the  Solent  from  Southampton 
to  Newport  in  the  Isle  of  Wight.  The  result  of 
his  experiment  is  told  in  a  paper  (on  Recent 
Progress  in  Telephony)  read  before  the  British 
Association  the  same  year.  From  some  cause, 
he  says,  the  cable  across  the  Solent  broke  down, 
and  as  it  was  of  great  importance  to  know  if  by 
any  means  it  was  possible  to  communicate  across, 
he  thought  the  opportunity  a  good  one  to  test 
the  ideas  which  had  been  promulgated  by  Pro- 
fessor Trowbridge.  He  therefore  put  a  plate  of 
copper  about  six  feet  square  in  the  sea  at  the  end 
of  the  pier  at  Ryde.  An  overhead  wire  passed 
from  there  to  Newport,  and  thence  to  the  sea 
at  Sconce  Point,  where  was  placed  another  cop- 
per plate.  Opposite,  at  Hurst  Castle,  was  a 
similar  plate,  connected  with  a  wire  which  ran 
through  Southampton  to  Portsmouth,  and  terr 


74     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

minating  in  another  plate  in  the  sea  at  Southsea 
Pier.  Thus  there  was  a  complete  circuit,  if  the 
water  be  included,  running  from  Southampton 
to  Southsea  Pier  (twenty-eight  miles),  across 
the  sea  to  Ryde  (six  miles),  thence  through 
Newport  to  Sconce  Point  (twenty  miles),  across 
the  water  again  to  Hurst  Custle  (one  and  a 
half  miles),  and  thence  back  to  Southampton 
(twenty-four  miles). 

The  account  goes  on  to  say  that  loud-speaking 
Gower-Bell  telephones  were  first  connected  in  the 
circuit,  but  it  was  found  that  conversation  was 
impossible.  Then,  at  Southampton  and  New- 
port, a  Theiler's  sounder,  or  buzzer  was  tried, 
and  with  it,  a  Morse  key,  and  thirty  Leclanche 
cells  at  Southampton,  it  was  possible  to  hear  the 
Morse  signals  in  a  telephone  at  Newport,  and 
vice  versa.* 

Although,  in  consequence  of  the  repair  of  the 
cable  the  next  day,  any  further  experimenting 
was  unnecessary,  Preece  did  not  permit  his  in- 
terest in  the  subject  to  flag,  and  during  the  next 
few  years  no  opportunity  was  neglected  that 
might  add  to  his  knowledge  in  regard  to  wire- 
less telegraphy. 

This  Solent  experiment  was,  of  course,  one  of 
conduction ;  but  his  attention  was  now  to  be 

*  Major  Cardew,  R.  E.,  introduced,  in  1886,  a  similar  system 
in  connection  with  our  military  telegraphs,  which  is  much  used 
to  bridge  over  broken  or  badly  insulated  wires. 


LAW   OF  INDUCTION.  75 

drawn  to  communication  by  induction.  Curious 
cases  of  telephones  picking  up  telegraphic  sig- 
nals from  distant  circuits  ever  and  anon  occurred 
to  give  fresh  stimulus  to  inquiring  minds,  and  to 
act,  as  it  were,  as  way-marks  to  investigation. 
One  of  the  most  striking  instances  of  the  kind  is 
that  known  as  the  Gray's  Inn  Road  case,  which 
occurred  in  1884.  From  insulated  wires  buried 
in  iron  tubes  beneath  the  road  it  was  found  that 
messages  in  course  of  transmission  could  be  read 
upon  telephone  circuits  carried  on  poles  over  the 
roofs  of  houses  eighty  feet  high. 

Here  there  seemed  to  be  a  clear  case  of  the 
operation  of  the  principle  or  law  of  induction,  as 
described  in  the  opening  chapter.  It  was  not 
safe,  however,  to  accept  it  as  such  without  fur- 
ther evidence,  as  there  was  just  the  possibility 
that  the  phenomenon  might  have  been  caused 
by  earth  conduction.  In  order  to  put  the  matter 
to  a  thorough  test,  and  also  to  discover  to  what 
distance  the  parallel  wires  could  be  removed 
from  each  other  before  the  inductive  influence 
failed  to  operate,  Preece  instituted  a  series  of 
experiments  on  the  town-moor  of  Newcastle 
(1885).  Two  quadrangles  of  insulated  wire 
were  laid  down  parallel  to  each  other  and  quar- 
ter of  a  mile  apart.  When  intermittent  electri- 
cal currents  were  set  up  in  one  of  these  sets  of 
wires  or  circuits,  they  could  be  distinctly  heard 
through  a  telephone  in  the  other  circuit.  The 


76     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

sides  of  these  squares  were  440  yards  in  length, 
and,  as  in  other  experiments  which  followed,  it 
was  found  that  as  soon  as  the  distance  between 
the  parallel  wires  began  to  exceed  the  length  of 
the  wires  the  "  induced  "  current  in  the  second 
wire  commenced  to  fall  off. 

One  of  the  most  interesting  of  Sir  William 
Preece's  experiments  of  this  description  took 
place  in  1886  on  the  banks  of  the  Severn, 
between  Gloucester  and  Bristol,  where  for  some 
fourteen  miles,  with  an  average  distance  apart 
of  four  and  a  half  miles,  there  was  an  ab- 
sence of  intermediate  lines  that  could  have 
a  disturbing  influence.  The  experiments  were 
conclusive,  though  unsatisfactory  in  so  far  as 
they  showed  that  the  "  range  of  audibility  "  with 
the  apparatus  employed  had  been  exceeded.  In- 
cidentally the  interesting  fact  came  out  that  the 
results  were  much  the  same  whether  the  circuits 
were  metallic  throughout  or  earthed  at  the 
ends. 

In  the  same  year  (1886)  a  similar  series  of 
experiments  was  conducted  on  a  wide  stretch  of 
sand  at  Porthcawl,  in  South  Wales,  when  the 
effect  of  suspending  one  circuit  in  the  air  above 
the  other  was  tried.  From  these  investigations 
the  conclusion  was  drawn  that  the  magnetic  field 
permeates  the  earth  as  well  as  the  air,  and  that 
if  a  circuit  were  arranged  in  a  space  beneath  the 
surface  of  the  ground  a  current  could  be  induced 


INTERESTING   EXPERIMENTS.  77 

in  it  from  a  superimposed  circuit  above  ground. 
This  inference  was  some  months  later  put  to  a 
successful  test  at  the  Broomhill  Colliery,  by  Mr. 
Heaviside,  one  of  Mr.  Preece's  assistants.  An 
equilateral  triangle  of  insulated  wire  three  quar- 
ters of  a  mile  in  length  each  side,  was  arranged 
in  a  horizontal  plane  at  the  bottom  of  the  colliery, 
360  feet  below  the  surface  of  the  ground.  A 
similar  triangle  was  placed  above  ground,  exactly 
over  and  parallel  to  the  former,  and  between  the 
telephones  in  the  two  circuits  communication  was 
successfully  established. 

Similar  and  highly  interesting  experiments 
were  conducted  the  same  year  (1886)  across  the 
Mersey  at  Liverpool,  and  between  Shrewsbury 
and  Much  Wenlock. 

It  is  unnecessary  to  go  into  details  of  all  the 
investigations  instituted  by  this  indefatigable 
worker;  but  two  or  three  sets  of  experiments 
carried  out  in  Scotland  and  Wales  respectively 
call  for  especial  mention.  The  first  of  the  series 
took  place  in  1892  between  Lavernock  Point  on 
the  Bristol  Channel,  and  the  two  near-lying 
islands  of  Flat  Holm  and  Steep  Holm.  The  ac- 
companying sketch-map  (Fig.  n)  shows  the 
position  of  the  two  islands,  the  first  named  being 
3.3  miles  distant  from  Lavernock  Point,  and  the 
other  5.35  miles  distant.  At  the  Point  two  thick 
copper  wires,  bound  together  so  as  to  form  one 
circuit,  were  stretched  on  poles  for  a  distance  of 


78     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

1,267  yards,  and  then  conducted  to  earth,  which 
completed  the  circuit. 

In  addition  to  this  three  other  wires  were  laid 
down,  600  yards  from  the  first  and  parallel  to  it. 
Two  of  them  were  covered  with  gutta-percha, 
the  third  was  left  bare ;  the  ends  of  all  three  were 


FIG.  ii. 

buried  in  the  ground.  One  of  the  insulated  lines 
was  attached  to  an  iron  wire  to  represent  a  cable. 
The  current  on  shore  was  generated  by  a  port- 
able engine  working  an  alternator  transmitting 
192  complete  alternations  per  second  of  a  maxi- 
mum intensity  of  fifteen  amperes.  The  receiv- 
ing circuits  on  Flat  Holm  and  Steep  Holm  con- 
sisted of  gutta-percha  covered  wires  600  yards  in 


TRIALS   IN   BRISTOL   CHANNEL.  79 

length,  laid  parallel  to  the  lines  on  shore,  and 
ending  in  each  case  in  the  water.  The  alternat- 
ing currents  were  broken  up  into  Morse  signals, 
and  were  received  on  the  secondary  circuit  by  a 
couple  of  telephones.  The  transmission  to  Flat 
Holm  was  perfect ;  to  Steep  Holm  it  was  not  so 
satisfactory :  though  the  signals  were  perceptible, 
conversation  was  out  of  the  question. 

Other  experiments  were  made  by  means  of  a 
steam  launch  carrying  an  insulated  copper  wire 
half  a  mile  in  length.  One  end  of  this  wire  was 
attached  to  a  buoy  in  such  a  way  that  it  could  be 
stretched  between  the  latter  and  the  launch  either 
above  the  water  or  for  the  most  part  submerged. 
Near  the  shore  communication  in  both  cases  was 
good ;  but  so  soon  as  the  secondary  circuit  was 
removed  a  mile  from  the  transmitting  station  the 
signals  were  only  received  when  the  wire  was 
out  of  the  water. 

The  end  aimed  at  in  these  experiments  was 
two-fold :  ( i )  To  test  the  practicability  of  estab- 
lishing a  system  of  signaling  without  wires 
between  the  shore  and  the  lighthouse  situated  on 
Flat  Holm,  and  (2)  to  determine  the  effects  due 
to  earth  conduction  from  those  due  to  electro- 
magnetic induction.  In  the  result  Preece  came 
to  the  conclusion  either  that  the  electromagnetic 
waves  of  energy  are  dissipated  in  the  sea-water, 
which  is  a  conductor,  or  else  that  they  are  re- 
flected from  the  surface  of  the  water  like  rays  of 


80    THE  STORY  OF  WIRELESS  TELEGRAPHY. 

light.  Later  experiments,  at  Conway  in  particu- 
lar, tended  to  prove  that  these  waves  are  trans- 
mitted to  considerable,  though  as  yet  unknown, 
distances  through  water. 

Another  important  series  of  experiments  made 
by  the  then  chief  engineer  to  the  post-office  took 
place  on  Loch  Ness,  which  forms  part  of  the 


FIG.  12. 

waterway  known  as  the  Caledonian  Canal,  and 
has  a  telegraph  on  each  side  of  it.  Though  these 
lines  are  about  a  mile  and  a  quarter  apart,  it  was 
found  to  be  an  easy  matter  to  send  messages 
across  either  by  Morse  signals  or  by  means  of 
the  telephone.  Somewhat  later  signals  were 
passed  between  the  Island  of  Arran  and  Kin- 
tyre,  across  Kilbrannan  Sound,  a  distance  of 
four  miles  (see  Fig.  12). 


CONCLUSIONS.  8 1 

A  similar  success — and  with  Sir  William 
Preece  a  success  in  these  experiments  always 
meant  a  commercial  success — on  the  same  lines 
was  obtained  in  March,  1895.  Tne  cable  con- 
necting the  Island  of  Mull  with  the  mainland 
near  Oban  having  been  broken,  it  was  decided, 
pending  the  arrival  of  the  cable  ship  charged 
with  repairs,  to  establish  communication  across 
the  Channel  by  inductive  means.  The  width  of 
the  Channel  at  the  point  selected  for  the  experi- 
ment varied  from  one  and  a  quarter  to  two  miles. 
An  overhead  wire,  well  adapted  to  the  object  in 
view,  existed  skirting  the  coast  of  the  island 
between  Craigmore  and  Aros.  On  the  mainland, 
parallel  to  this  wire,  another  with  gutta-percha 
insulation  was  laid  along  the  ground  for  a  dis- 
tance of  a  mile  and  a  half.  One  end  of  it  was 
earthed  in  a  running  stream,  the  other  end  in  the 
sea.  A  rheotome,  or  make-and-break  wheel,  an 
ordinary  battery,  a  Morse  key,  and  a  telephone 
to  act  as  receiver  were  included  in  each  circuit. 
The  installation  was  perfectly  successful,  the  or- 
dinary service  being  conducted  by  this  means 
until  the  cable  had  been  repaired. 

As  the  result  of  his  many  and  varied  experi- 
ments in  connection  with  wireless  telegraphy,  Sir 
William  Preece  arrived  at  definite  conclusions  in 
regard  to  the  part  played  by  the  earth  in  electro- 
magnetic operations.  The  earth,  so  he  holds, 
acts  simply  as  a  conductor,  and  as  a  rule  it  is  a 
6 


82     THE   STORY   OF   WIRELESS   TELEGRAPHY. 

very  poor  conductor,  deriving  its  conducting 
property  principally  from  the  moisture  it  con- 
tains. On  the  other  hand,  the  resistance  of  the 
"  earth  "  between  the  two  earth-plates  of  a  good 
circuit  is  practically  nothing.  Hence  it  follows 
that  the  mass  of  earth  which  forms  the  return 


FIG. 


portion  of  a  circuit  must  be  very  great  indeed, 
for  we  know  that  the  resistance  of  a  circuit  in- 
creases with  its  specific  resistance  and  length, 
and  diminishes  with  its  sectional  area.  Now,  if 
the  material  forming  the  "  earth  "  portion  of  the 
circuit  were,  like  the  sea,  homogeneous,  the  cur- 
rent-flow between  the  earth-plates  would  follow 
innumerable  but  definite  stream  lines,  which,  if 
traced  and  plotted  out,  would  form  a  hemis- 
pheroid.  These  lines  of  current  have  been  traced 
and  measured.  A  horizontal  plan  on  the  surface 
of  the  earth  is  of  the  form  illustrated  in  Fig.  13, 
while  a  vertical  section  through  the  earth  is  of 
the  form  shown  in  Fig.  14. 

With  earth-plates  1,200  yards  apart  these  cur- 
rents have  been  found  on  the  surface  at  a  dis- 


CONCLUSIONS.  83 

tance  of  half  a  mile  behind  each  plate ;  and,  in  a 
line  joining  the  two,  they  are  evident  at  a  similar 
distance  transversely  at  right  angles  to  this  line. 
Now  this  hemispheroidal  mass  could  be  re- 
placed electrically  by  a  resultant  conductor  (R, 
Fig.  14)  of  a  definite  form,  resistance,  and  posi- 


FlG.    14. 

tion ;  and,  in  considering  the  inductive  action 
between  the  two  circuits  having  earth  returns,  it 
is  necessary  to  estimate  the  position  of  the  imag- 
inary conductor. 

If  the  material  of  the  earth  be  variable  and 
dry  the  hemispheroid  must  become  very  much 
deformed  and  the  section  very  irregular,  the  lines 
of  current-flow  must  spread  out  further,  but  the 
principle  is  the  same,  and  there  must  be  a  re- 
sultant return.*  The  general  results  of  experi- 
ments at  Frodsham  indicate  that  the  depth  of  the 
resultant  earth  was  300  feet,  while  those  at  Con- 
way  are  comparable  with  a  depth  of  350  feet.  In 
the  case  of  Frodsham  the  primary  coil  had  a 
length  of  300  feet,  while  at  Conway  the  length 

*"  Signaling  through  Space,"  by  W.  H.  Preece,  C.  B., 
F.  R.  S. 


84     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

was  1,320  feet.  At  Loch  Ness  and  between 
Arran  and  Kintyre,  where  the  parallel  lines 
varied  from  two  to  four  miles,  the  calculated 
depth  was  found  to  be  about  900  feet.  The 
depth  of  this  resultant  must,  therefore,  increase 
with  the  distance  separating  the  earth-plates,  and 
this  renders  it  possible  to  communicate  by  induc- 
tion from  parallel  wires  over  much  longer  dis- 
tances than  would  otherwise  be  possible. 


CHAPTER  VI 

Willoughby  Smith's  experiments  in  conduction  through 
water  and  earth — Smith  and  Granville's  experiments 
at  the  Needles  Lighthouse — Application  of  their 
method  to  the  Fastnet  Lighthouse — The  investiga- 
tions of  G.  A.  Stevenson  in  electromagnetic  conduc- 
tion and  induction — Preece  and  Stevenson's  experi- 
ments awaken  interest  on  the  Continent — Professor 
Rathenau's  investigations — Evershed's  Experiments 
at  the  Goodwin  Lightship— Preece's  experiments  at 
the  Skerries  and  Rathlin  Island— His  views  as  to 
earth-conduction,  etc. 

REFERENCE  has  been  made  in  the  foregoing 
chapter  to  views  enunciated  by  Mr.  Willoughby 
S.  Smith  in  1883,  in  regard  to  signaling  to  and 
from  trains,  and  the  influence  they  undoubtedly 
had  upon  Edison's  subsequent  experiments  in  the 
same  field.  From  the  suggestions  he  then  threw 
out  it  will  be  seen  that  Smith's  investigations 
were  at  first  directed  more  particularly  to  electro- 
magnetic induction  as  a  means  of  communicating 
between  distant  places ;  but  not  arriving  at  the 
results  he  desired  by  that  means,  he  began  to  try 
what  could  be  done  by  conduction  through  earth 
and  water.  The  principle  upon  which  he  went 
to  work  is  fully  set  forth  in  a  communication  he 

85 


86     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

made  to  the  Electrician  (Nov.  2,  1888)  in  regard 
to  the  application  of  his  method  to  lighthouses 
and  to  vessels  within  a  certain  distance  of  the 
shore.  In  the  article  in  question  he  explains 
how  a  wooden  bathing-hut  on  a  sandy  beach  was 
utilized  as  a  shore  station.  From  it  were  laid 
two  insulated  copper  wires  115  fathoms  in 
length.  "  The  ends  of  the  wires,  scraped  clean," 
he  says,  "  were  twisted  round  anchors,  their  posi- 
tion being  marked  by  buoys  about  one  hundred 
fathoms  apart,  and  in  about  six  fathoms  of 
water.  Midway  between  the  two  a  boat  was 
anchored  with  a  copper  plate  hanging  fore  and 
aft  about  ten  fathoms  apart,  and  consequently 
about  forty-five  fathoms  from  either  end  of  the 
anchored  shore  wires.  This  boat,  which  repre- 
sented the  sea  station,  would,"  he  continues, 
"  have  been  much  better  for  my  purpose  had  it 
been  of  metal,  for  then  I  should  have  used  it 
instead  of  one  of  the  collecting  plates,  as  the 
larger  the  surface  of  these  plates  the  better  the 
results  obtained." 

Messages  by  this  means  were  passed  with 
"  distinctness  and  ease,"  and  accordingly  a  patent 
for  the  method  was  secured  in  June,  1887.  The 
diagram  given  herewith  (Fig.  15)  explains  the 
modus  operandi.  A  is  a  two-conductor  cable 
proceeding  from  the  signal  station  B  on  shore 
toward  the  rock  C.  A  short  distance  from  the 
shore  the  cable  divides,  one  of  the  conductors 


LIGHTHOUSE   COMMUNICATION.          87 

going  off  at  right  angles  to  the  submerged 
metallic  plate  D  the  other  terminating  in  like 
manner  at  plate  E.  Opposite  them  are  two  other 
submerged  plates,  F  F,  connected  by  insulated 
conductors  leading  to  a  telephone  of  low  resist- 


FIG.  15. 

ance  in  the  lighthouse  H.  Communication  be- 
tween shore  and  rock  is  carried  on  by  means 
of  an  interrupter  or  reverser  I  and  battery  K  at 
the  shore  end  of  the  cable  and  a  telephone  in  the 
lighthouse ;  and  vice  versa  for  communication 
between  rock  and  shore.  Smith's  specification 
shows  how  the  system  may  be  equally  well 
adapted  for  communication  between  passing  ves- 
sels and  the  shore. 

In  collaboration  with  Mr.  William  P.  Gran- 
ville,  Willoughby  Smith  subsequently  consider- 


88     THE   STORY   OF  WIRELESS   TELEGRAPHY. 


ably  developed  the  method  above  described. 
They  found  that  if  the  rock  was  at  a  considerable 
distance  from  the  shore  the  transmission  of  sig- 
nals was  greatly  facilitated  by  submerging  as 
near  as  practicable  to  the  rock  a  transformer 


FIG.  16. 


which  has  its  primary  or  high  resistance  circuit 
coupled  to  the  two  insulated  conductors  from 
the  shore,  or  to  a  single  insulated  conductor  and 
earth-plate  or  metallic  mass,  as  shown  in  Fig.  16, 
while  the  ends  of  the  secondary  or  low  resistance 
coil  are  coupled  to  other  insulated  conductors 
leading  to  two  submerged  earth-plates  or  masses 
in  the  vicinity  of  the  rock.  The  arrangement 
provides  also  for  the  use  of  a  transformer  on 
the  rock.  This  method,  it  will  be  seen,  is 


STEVENSON'S   RESEARCHES.  89 

Preece's,  as  worked  between  Lavernock  and  Flat 
Holm,  with  a  little  modification. 

By  arrangement  with  the  Trinity  House  au- 
thorities this  system  was,  in  1892,  put  to  a  suc- 
cessful test  at  the  Needles  Lighthouse,  and  was 
subsequently  applied  to  the  lighthouse  on  the 
Fastnet  Rocks,  off  the  southwest  corner  of  Ire- 
land, one  of  the  most  inaccessible  beacons  on  the 
British  coasts,  where  it  is  still  in  operation. 

Equally  interesting,  although  hardly  so  suc- 
cessful as  those  just  described,  were  the  re- 
searches of  Mr.  Charles  A.  Stevenson,  of  the 
Northern  Lighthouse  Board,  in  much  the  same 
field — that  is,  between  shore  and  ship,  and  shore 
and  lighthouse,  and  vice  versa.  Stevenson's  in- 
vestigations began  in  1892,  and  were  continued 
for  several  years,  the  results  arrived  at  being 
given  in  two  papers  read  before  the  Royal 
Society  of  Edinburgh  in  January,  1893,  and 
March,  1894,  respectively.  This  experimenter 
struck  out  and  tested  two  methods.  In  each  he 
starts  with  a  cable  stretched  and  submerged 
from  the  shore  seaward.  When,  in  the  first 
method,  a  ship,  which  is  provided  with  a  wire 
having  a  telephone  in  circuit,  that  is  stretched 
from  stem  to  stern  and  terminates  in  coils  dip- 
ping into  the  water,  approaches  or  crosses  the 
cable  at  right  angles,  or  nearly  so,  any  currents 
set  up  in  the  latter  from  the  shore  end  are  audible 
in  the  telephone  on  board.  This  method  was 


90     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

tested  by  means  of  a  boat  on  a  small  lake,  when 
the  currents  in  the  submerged  wire  could  be 
plainly  heard  in  the  telephone  at  a  distance  of 
300  feet. 

Mr.  Stevenson's  second  method  consisted  in 
letting  down  into  the  sea  over  a  vessel's  side,  by 
means  of  a  wire  200  feet  long,  a  three-foot 
electromagnet.  Interruptions  in  the  current 
from  six  dry  cells  were  audible  on  the  telephone 
at  a  distance  of  forty  feet  in  air,  while  with 
double  the  number  of  dry  cells  the  sounds  could 
be  heard  through  sixty  feet  of  water. 

Stevenson  subsequently  changed  his  base  of 
operations  from  electrostatic  or  electromagnetic 
conduction  to  simple  induction,  using  insulated 
coils  of  wire,  as  being,  according  to  his  view, 
better.  He  made  a  large  number  of  experiments, 
in  the  laboratory  and  elsewhere,  with  a  view  to 
working  out  a  system  that  might  be  adopted 
for  communication  between  the  lighthouse  on  the 
island  of  Muckle  Flugga,  in  the  Shetlands,  and 
the  mainland.  It  is  not  necessary  to  weary  the 
reader  with  details  of  those  investigations. 
Suffice  it  to  say  that,  though  the  Commissioners 
of  Northern  Lighthouses,  being  impressed  by  the 
experiments  shown  them  by  Mr.  Stevenson 
(when  it  was  proved  that  the  distance  between 
Muckle  Flugga  and  the  mainland  could  be  satis- 
factorily bridged  by  means  of  a  battery  of  100 
dry  cells,  with  1.2  ohms  resistance  each  and  1.4 


COILS   AND   PARALLEL   WIRE.  91 

volts),  decided  on  adopting  the  system  for  com- 
munication with  the  North  Unst  Lighthouse,  yet, 
in  the  end,  the  idea,  in  consequence  of  financial 
difficulties,  was  abandoned. 

Referring  to  his  experiments  in  regard  to  the 
proposed  Muckle  Flugga  installation  in  a  com- 
munication to  the  Journal  of  the  Institute  of 
Electrical  Engineers,  Mr.  Stevenson  says : 
"  Theory  and  formulae  give  one  the  impression 
at  first  sight  that  a  single  outstretched  wire  is 
always  the  best  .  .  .  but  formulae,  if  they  are 
to  be  practised,  ought  to  take  into  account  a  lim- 
ited area  and  workable  amounts  of  resistance, 
current,  etc.,  and  then  the  fact  is  disclosed  that 
the  coiling  of  wires  (whether  condensers  be  used 
with  them  or  not)  becomes  an  advantage  for 
most  work  which  the  engineer  will  be  called  upon 
to  deal  with. 

"  It  is  not  necessary,  as  has  been  stated,  that 
the  coils  should  be  identical  in  size  and  shape. 
Far  from  it;  each  case  must  be  treated  for  size 
and  configuration  by  itself.  .  .  . 

"  I  have  made  numerous  trials  of  the  coil 
versus  the  parallel  wire  system  since  1891,  and  I 
have  found — and  other  observers  also  seem  to 
have  found — that  it  is  not  practical  to  work  the 
latter  more  than  three  or  four  times  the  length 
of  base ;  whereas  by  coils  I  have  found  it  possible 
to  work  many  times  this  diameter.  Thus  in 
1892,  at  the  Isle  of  May  Lighthouse,  I  signaled 


92    THE  STORY  OF  WIRELESS  TELEGRAPHY. 

to  a  distance  360  times  the  diameter  of  an  electro- 
magnet coil  with  currents  from  a  De  Meriten's 
magneto-electric  machine.  Again,  at  Murray- 
field,  I  signaled  four  times  the  base  with  five  dry 
cells ;  and  I  have,  in  Edinburgh,  a  coil  with  iron 
cone  seventeen  inches  diameter,  which,  with  one 
cell,  can  easily  signal  through  a  space  twenty- 
five  times  its  diameter." 

During  these  prolonged  experiments  Steven- 
son developed  a  method  of  wireless  telegraphy 
for  guarding  a  dangerous  coast.  This  was  by 


FIG.  17. 

means  of  a  wire  many  miles  in  length  suitable 
for  communicating  warning  signals  to  vessels  on 
board  of  which  were  detectors  of  small  dimen- 
sions. "  This  guarding  of  a  dangerous  stretch 
of  coast,"  he  says,  in  a  discussion  on  Magnetic 
Space  Telegraphy  at  the  Institution  of  Electrical 
Engineers,  Jan.  12,  1899,  "  appears  to  me  to  be 
the  most  important  application  of  telegraphy  by 
induction.  There  are  two  main  systems,  both  of 
which  I  have  tried.  First,  there  is  the  principle 
of  laying  down  a  submarine  cable  along  the  line 
of  coast  (see  Fig.  17). 


GERMAN  INVESTIGATIONS.  93 

"  In  this  case  the  currents  set  up  in  the  cable 
have  to  be  sent  only  through  the  sheet  of  water 
to  the  vessel — say  twenty  fathoms,  or  120  feet, 
or,  if  an  electromagnet  be  let  down  from  the 
ship,  only  four  or  five  fathoms.  There  are,  how- 
ever, certain  objections  to  this  system:  for 
instance,  the  first  cost  of  cable  and  maintenance 
of  it  are  important  considerations." 

His  second  system  consisted  of  the  erection  of 
a  pole  line  on  shore,  either  along  the  stretch  of 
coast,  or  in  the  form  of  a  coil  on  a  peninsula. 
The  main  difference  between  this  and  the  first 
method  lay  in  the  fact  that  the  currents  set  up 
in  the  land  line  had  to  be  sent  several  miles  out 
to  a  ship  in  place  of  only  a  few  yards,  but  the 
submarine  cable  was  done  away  with.  Steven- 
son says :  "  I  have  tried  this  system  with  two 
miles  of  pole  line  and  a  coil  about  a  quarter  of 
a  mile  off  the  line  with  perfect  and  never-failing 
success." 

These  experiments  of  Stevenson,  together  with 
those  of  Preece,  and  others,  attracted  so  much 
attention  on  the  Continent,  and  especially  in  Ger- 
many, that  Prof.  Emil  Rathenau,  of  Berlin, 
at  the  request  of  the  German  Imperial  Marine, 
undertook,  with  the  assistance  of  Drs.  Rubens 
and  W.  Rathenau,  to  make  a  thorough  in- 
quiry into  the  possibility  of  establishing  tele- 
graphic communication  through  the  medium  of 
water  as  a  conductor.  As  regards  method,  those 


94    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

he  employed  did  not  differ  materially  from  the 
double  pair  of  metallic  plates  used  by  Morse, 
only  in  consequence  of  the  technical  improve- 
ments made  in  electrical  apparatus  in  recent 
years,  Rathenau  was  enabled  to  lay  down  a  more 
perfect  installation. 

These  experiments  took  place  (in  1894)  on  a 
small  lake  near  Potsdam,  known  as  the  Wannsee, 


FIG.  1 8. 

on  account  of  the  facilities  as  regards  apparatus 
afforded  by  the  electric-light  station  at  Alsen. 
The  primary  circuit  contained  a  battery  of 
twenty-five  cells  (A  B  in  Fig.  18),  an  interrupter 
driven  by  a  motor,  a  set  of  resistance  coils  R,  an 
ampere-meter  A,  and  a  volt-meter  V,  as  well  as  a 
Morse  key  T.  The  line  ended  in  two  zinc  plates 
E  E,  fifteen  square  meters  in  surface  measure- 
ment, sunk  in  the  water,  and  50x5  meters  apart. 
The  receiving  circuit  consisted  of  two  zinc 


RATHENAU  AT  WANNSEE. 


95 


plates  (e,  e),  four  square  meters  in  surface 
measurement,  which  were  suspended  in  the 
water  from  two  boats,  whose  distance  apart 
varied  from  50  to  300  meters;  the  plates  being 
connected  the  one  with  the  other  by  means  of  a 
wire,  to  which  was  attached  a  telephone  N, 
stretched  above  the  water. 

The  primary  current  at  disposal  did  not  exceed 
three  amperes  in  intensity,  and  it  could  only  be 
broken  150  times  per 
second,  while  the  sen- 
sitiveness of  the  tele- 
phone is  held  to  be 
the  greatest  for  a  fre- 
quence of  600  impulses 
per  second.  Yet  in 
spite  of  these  unfavor- 
able conditions  the 
transmitted  signals 
were  clearly  audible 
to  an  unaccustomed 
ear  from  the  sending 
station  P  P  (Fig.  19) 
to  the  boat  stationed 
off  New-Cladow,  a  distance  of  4.5  kilometers. 
Nor  was  the  distinctness  of  the  signals  much 
interfered  with  when  the  receiving  station  was 
removed  to  the  position  marked  3  in  the  sketch- 
map,  although  the  island  (as  indicated)  stood  in 
the  way. 


FIG.  19. 


96    THE  STORY   OF  WIRELESS  TELEGRAPHY. 

Professor  Rathenau  remarks  that  with  more 
favorable  conditions — that  is,  if  the  current  in 
the  primary  circuit  had  been  stronger,  or  there 
had  been  a  greater  distance  between  the  plates 
of  that  circuit,  as  well  as  quicker  interruptions, 
or  a  greater  number  of  impulses  in  the  primary 
circuit,  and  lastly,  if  a  telephone  had  been  em- 
ployed which  had  been  carefully  timed  to  the 
number  of  current-breaks  in  the  transmitting  cir- 
cuit— much  better  results  would  have  been  ob- 
tained. 

It  is  worthy  of  note  that,  like  Sir  William 
Preece  and  others,  Professor  Rathenau  found 
that  when  two  conductors  connected  with  the 
poles  of  a  source  of  electricity  are  carried  to 
earth,  whether  the  earth  be  moist  or  dry,  streams 
of  electricity  spread  out  on  every  side,  just  as  in 
water ;  and  he  sees  in  this  phenomenon  a  possible 
explanation  of  the  inference  so  often  noticed  be- 
tween near-lying  telegraph  and  telephone  wires, 
and  attributed  by  many  to  the  influence 
of  induction.  In  these  streams  of  electricity 
spreading  in  all  directions  through  the  solid 
earth,  Professor  Rathenau  saw  the  possibility  of 
a  system  of  wireless  telegraphy  adapted  for 
continental  (as  distinguished  from  intracontinen- 
tal  or  transoceanic)  use.  The  idea  was  taken  up 
by  Strechner,  who  somewhat  later  made  a  num- 
ber of  interesting  and,  so  far  as  they  went,  suc- 
cessful experiments  with  a  view  to  seeing  how 


EXPERIMENTS  AT  MENAI  STRAITS.        97 

far  earth  conduction  could  be  utilized.  He  had 
the  satisfaction  of  getting  results  at  the  distance 
of  seventeen  kilometers;  but  the  cost  at  which 
they  were  obtained  rendered  his  method  prac- 
tically inoperative.  He  had  not,  of  course,  hit 
upon  the  right  principle,  which  appears  to  have 
been  reserved  for  Messrs.  Orling  and  Armstrong 
(whose  system  we  shall  presently  have  to  dis- 
cuss) to  discover. 

While  on  this  subject  of  communication  with 
lighthouses  and  lightships  it  may  be  well  to  refer 
to  two  or  three  other  experiments  of  the  kind, 
although  they  take  us  a  little  too  far  ahead  as 
regards  date.  In  1896  Mr.  Evershed  made  trial 
of  a  method  of  using  coils  which  he  had  patented 
several  years  before  on  the  North  Sand  Head 
(Goodwin)  lightship.  One  end  of  a  cable  was 
coiled  in  a  ring  on  the  sea-bottom,  enclosing  the 
entire  area  covered  by  the  ship  in  swinging  to 
and  fro  with  the  tide,  the  other  end  being  con- 
nected with  the  shore.  The  ship  itself  was  en- 
circled by  another  coil  above  the  water-line.  The 
two  coils  were  only  about  200  fathoms  apart; 
but  for  various  reasons — the  influence  of  the  ves- 
sel's iron  hull  and  the  screening  effect  of  the  sea- 
water — effective  signaling  was  out  of  the  ques- 
tion. 

A  year  or  two  later  (1899)  Preece  conducted 
some  careful  experiments  on  the  Menai  Straits 
"  which  determined  the  fact  that  the  maximum 
7 


98     THE   STORY   OF   WIRELESS   TELEGRAPHY. 

effects  with  telephones  are  produced  when  the 
parallel  wires  are  terminated  by  earth-plates  in 
the  sea  itself."  It  became  desirable  to  establish 
communication  between  the  lighthouse  on  the 
rocks  known  as  the  Skerries  and  the  coastguard 
station  at  Cemlyn  on  the  mainland  of  Anglesea, 


ANGLESEY 


SCALE  i  INCH  TO  MILE 

FIG.  20. 

and  it  was  decided  to  do  this  by  means  of  wire- 
less telephony.  A  wire  750  yards  in  length  was 
stretched  along  the  Skerries,  and  on  the  main- 
land one  of  3^  miles  from  a  point  opposite  the 
Skerries  to  Cemyln,  the  average  distance  between 
the  two  being  2.8  miles.  Each  line  terminates 
by  an  earth-plate  in  the  sea.  The  connections 
used  are  shown  in  the  diagram  (Fig.  20).  Tele- 
phonic communication  is  easily  maintained  and 
the  service  is  said  to  be  excellent. 


COMMUNICATION   WITH   RATHLIN    ISLAND.    99 

The  same  system  was  subsequently  adopted 
for  communication  between  Rathlin  Island  on 
the  north  coast  of  Ireland,  and  the  mainland.  The 
east  and  west  portions  of  the  island  of  Rathlin 
are  about  eight  miles  from  the  mainland,  but  a 
tongue  of  land  projects  southward  to  within  a 


FIG.  21. 


distance  of  four  miles  (Fig.  21).  Communica- 
tion was  required  between  the  lighthouse  near  the 
northeastern  corner  of  the  island  and  the  main- 
land, and  it  was  a  question  whether  an  over- 
head line  across  the  neck  of  the  southern  penin- 
sula would  be  sufficient.  This  proved  to  be  the 
case,  and  thus  wireless  communication,  both  tele- 
graphic and  telephonic,  was  established  across 
the  sea. 


100    THE  STORY  OF  WIRELESS  TELEGRAPHY. 

At  this  time  Preece  seemed  to  hold  these  ex- 
periments as  conclusive  that  earth  conduction 
had  nothing  to  do  with  the  results  obtained. 
Other  authorities,  however,  such  as  Sir  Oliver 
Lodge,  Charles  A.  Stevenson,  Professor  Rathe- 
nau,  of  Berlin  (cognate  researches  by  whom  we 
shall  shortly  have  to  describe),  and  others,  in- 
clined to  the  opinion  that  the  effect  is  partly  in- 
ductive and  partly  conductive. 

As  the  result  of  his  many  experiments  Preece 
came  to  the  conclusion  that  "  although  communi- 
cation across  space  has  thus  been  proved  to  be 
practical  in  certain  conditions,  those  conditions 
do  not  exist  in  the  case  of  isolated  lighthouses 
and  lightships,  cases  which  it  was  specially  de- 
sired to  provide  for."  But  after  seeing  what 
was  subsequently  done  at  the  Fastnet  Light- 
house, Sir  William  no  doubt  changed  his  opinion 
in  this  respect. 


CHAPTER  VII 

Hertz's  great  discovery  of  electromagnetic  waves — His 
apparatus — Clerk  Maxwell's  hypothesis — Sir  Oliver 
Lodge  on  Maxwell  and  Hertz — The  identity  of  elec- 
tricity with  light — Professor  Hughes  and  his  researches 
— Sir  William  Crookes's  prediction — Hughes's  account 
of  his  experiments — His  wireless  telegraphy — Dis- 
couragement by  scientific  experts. 

THESE  later  installations  of  Sir  William  Preece 
— for  the  establishment  of  permanent  communi- 
cations at  the  Skerries,  Rathlin  Island,  and 
Lavernock  had  gone  beyond  the  experimental 
stage — did  not  at  the  time  attract  the  attention 
they  deserved,  and  would  otherwise  have  excited, 
because  of  the  sensation  awakened,  not  only  in 
1897,  when  the  new  discovery  first  became 
known,  but  since,  by  Marconi's  application  of 
Hertzian  waves  to  telegraphy.  Up  to  this  time, 
although  Hertz's  epoch-making  researches  were 
nearly  ten  years  old,  they  were  almost  wholly 
unknown  to  the  general  public.  Nor  in  all  prob- 
ability would  the  German  professor's  famous  dis- 
covery, whereby  Clerk  Maxwell's  mathematical 
deduction  as  to  the  existence  of  electromagnetic 
waves  was  lifted  into  the  clear  region  of  estab- 
lished fact,  have  become  generally  appreciated 
had  not  the  foundation  thus  laid  suddenly  found 


102      THE   STORY   OF  WIRELESS   TELEGRAPHY. 

a  builder  able  to  complete  the  edifice  by  the  re- 
alization of  its  potentialities  in  aerial  telegraphy. 

Hertz  has  recorded  how  his  interest  was  first 
awakened  in  regard  to  electrical  oscillations 
through  the  offer  of  a  prize  for  an  experimental 
proof  of  a  connection  betwixt  electro-dynamic 
forces  and  dielectric  polarization  in  insulators. 
Although  he  soon  relinquished  the  inquiry, 
which  he  took  up  at  the  suggestion  of  Von 
Helmholz,  under  whom  he  had  studied,  his  mind 
was  ever  after  on  the  lookout  for  phenomena 
that  seemed  to  point  in  the  direction  indicated. 
Hence  when  making  use  of  an  old  pair  of  coils 
or  spirals  of  insulated  wire  for  some  experi- 
ments in  the  course  of  a  lecture  he  was  giving 
at  Carlsruhe,  he  found  that  the  discharge  of  a 
small  Ley  den  jar,  or  of  an  induction  coil,  through 
one  of  the  spirals  resulted  in  the  setting  up  of 
an  induced  current  in  the  other,  provided  the  first 
spiral  had  a  small  "  spark-gap  "  in  its  circuit,  he 
was  not  slow  to  perceive  the  importance  of  the 
fact.  In  short,  in  that  casual  observation  lay  the 
germ  of  the  effective  spark-gap,  the  "  electric 
eye,"  as  Lord  Kelvin  has  called  it,  through  which 
Hertz  was  led  to  his  remarkable  discoveries. 

Those  discoveries,  and  the  apparatus  by  which 
he  was  enabled  to  make  them,  he  described  in  a 
series  of  papers  which  was  subsequently  pub- 
lished in  a  collected  form  under  the  title  of 
Electric  Waves.  His  apparatuses  were  remark- 


HERTZ'S   DISCOVERY.  103 

able  for  their  simplicity,  and  consisted  in  the 
main  of  an  exciter  or  radiator  and  a  receiver 
or  detector.  For  the  former  he  made  use  of  wire 
rectangles,  or  simple  rods  to  the  ends  whereof 
metallic  spheres  were  attached,  continuity  in 
either  case  being  broken,  and  the  distracted  ends 
fitted  with  round  knobs  (Fig.  22).  This  break 
in  the  wire  forms  the 
"  spark-gap,"  the  dis- 
covery of  which  was 
the  starting-point  o  f 
Hertz's  investigations. 

The  receiver  consisted  of  either  a  rectangle  or 
a  simple  circle  of  iron,  having  a  spark-gap  the 
same  as  the  exciter. 

When  through  such  a  circuit  as  the  exciter 
here  described  forms,  a  charge  is  sent  by  means 
of  a  condenser,  like  a  Ley  den  jar  or  a  small 
Ruhmhorff  induction  coil  (as  was  Hertz's  wont) 
an  electrical  discharge  of  short  sharply  defined 
duration  is  obtained.  By  such  a  discharge  a 
sudden  and  infinitely  rapid  disturbance  of  elec- 
trical equilibrium  is  set  up,  causing  an  excitation 
of  electrical  vibrations  of  great  velocity  in  the 
ether.  Vibrations  of  this  description  are  capable 
of  creating  in  another  circuit  of  similar  construc- 
tion, such  as  a  Hertz  detector,  disturbances  of  a 
like  nature  and  of  such  energy  as  to  be  percep- 
tible when  the  two  circuits,  that  is,  the  exciter 
and  receiver,  are  far  apart. 


104     THE  STORY  OF  WIRELESS  TELEGRAPHY. 

The  proof  that  the  rapid  changes  in  the  dis- 
charges are  really  vibrations  Hertz  established  in 
the  following  manner:  He  placed  opposite  the 
exciter  (Fig.  23)  a  second  circuit  abed,  which 
returns  upon  itself  as  far  as  the  short  air-gap 
a  d.  The  quick  current  changes  in  A  A  induce 
in  the  secondary  circuit 
equally  rapid  changes, 
which  announce  them- 
selves  by  sparks  between 
a  d.  In  these  effects  of 
induction  Hertz  was  able 
under  certain  conditions  to 
trace  resonance.  The 
conductor  a  b  c  d  is  a  form 
in  which  the  electricity  can 
make  oscillations  whose 
period  is  given  by  self-in- 
duction and  capacity.  If 
the  rapid  changes  of  elec- 
tricity are  really  oscillations,  their  inductive 
effects  can  only  call  forth  electrical  resonance  in 
abed  when  the  period  number  of  the  oscilla- 
tions agree  with  the  natural  period  number  of 
the  secondary  circuit. 

The  proper  oscillatory  duration  of  the  second- 
ary conductor  depends  on  its  self-induction  and 
capacity,  and  can  be  lowered  therefore  by  chang- 
ing the  capacity.  With  this  end  in  view  Hertz 
bound  the  ends  a  and  d  with  the  changeable 


ELECTRO  MAGNETIC  WAVES.  105 

plates  of  a  small  condenser  e  e,  wh'ose  variable 
capacity  then  determines  the  tone.  By  this 
means  he  was  able  to  prove  that  strong  sparks 
were  only  able  to  play  between  a  and  d  when 
the  plates  were  at  a  given  distance  from  each 
other,  while  by  the  increase  or  diminution  of  the 
distance  the  sparks  become  considerably  weaker. 
Thus  it  was  shown  experimentally  that  resonance 
takes  place  when  the  periods  in  the  exciting  and 
the  receiving  circuits  are  in  harmony. 

With  such  simple  apparatus  Hertz  reproduced 
all  the  phenomena  of  light,  including  those  of  re- 
flection and  refraction,  in  corresponding  electro- 
magnetic effects,  and,  in  accordance  with  Max- 
well's hypothesis,  he  showed  that  light  and  elec- 
tricity are  in  all  essential  particulars  identical. 

As  to  the  existence  of  the  electromagnetic 
waves,  Sir  Oliver  Lodge  tells  us  that  "  Maxwell 
and  his  followers  were  confident  that  the  proof 
would  come.  They  knew  the  rate  at  which  they 
would  go;  they  knew  that  they  would  go  slower 
in  glass  and  water  than  in  air;  they  knew  that 
they  would  curl  round  sharp  edges,  that  they 
would  be  partly  absorbed  but  mainly  reflected  by 
conductors,  that  if  turned  back  upon  themselves 
they  would  produce  the  phenomena  of  stationary 
waves,  or  interference,  or  nodes  or  loops.  It 
was  known  how  to  calculate  the  length  of  such 
waves,  and  even  how  to  produce  them  of  any 
required  or  predetermined  wave-length,  from 


I06     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

1,000  miles  to  a  foot.  Other  things  were  known 
about  them  which  would  take  too  long  to  enu- 
merate ;  any  homogeneous  insulator  would  trans- 
mit them,  would  repeat  or  concentrate  them  if  it 
were  of  suitable  shape,  would  reflect  none  of  a 
particular  mode  of  vibration  at  a  certain  angle, 
and  so  on." 

All  this  was  known,  but  Hertz  supplied  the 
verification.  "  He  inserted  suitable  conductors 
in  the  path  of  such  waves,  conductors  adapted 
for  the  occurrence  in  them  of  induced  electric 
oscillations,  and  to  the  surprise  of  every  one, 
himself  doubtless  included,  he  found  that  the 
secondary  electric  surgings  thus  excited  were 
strong  enough  to  display  themselves  by  minute 
electric  sparks."* 

Such  was  Hertz's  contribution  to  exact  sci- 
ence, and  it  would  be  extremely  difficult  to  over- 
estimate its  importance.  Sir  Oliver  Lodge,  one 
of  the  brightest  lights  of  contemporary  science, 
whom  we  have  just  quoted,  and  who  has  done 
more  than  any  one  else  in  England  to  make 
Hertz  and  his  work  known,  has  said,  speaking 
of  the  death  of  that  investigator  (which  occurred 
in  1894),  that  he  did  not  go  until  he  had 
"  effected  an  achievement  which  will  hand  his 
name  down  to  posterity  as  the  founder  of  an 
epoch  in  experimental  physics " ;  and  in  that 

*Signaling  through  Space  without  Wires,  by  Prof.  Oliver 
Lodge,  F.  R.  S.  (Third  Edition). 


ELECTRICITY   AND   LIGHT.  IOy 

high  eulogy  he  in  no  wise  exaggerates.  With- 
out Hertz's  brilliant  discoveries — and  he  pro- 
ceeded from  one  to  another  with  almost  startling 
rapidity,  measuring  the  waves  and  fixing  the 
rate,  proving  that  they  might  be  a  fraction  of  an 
inch  or  1,000  miles  in  length,  determining  their 
periodicity  to  be  about  one  hundred  millionth  of 
a  second,  waves  of  2.8  meters  in  length  having 
the  velocity  of  light,  or  186,000  miles  a  second, 
demonstrating  that  the  waves  could  be  reflected, 
deflected,  and  secured,  and  determining  their 
nodal  points  and  outline,  all  within  the  walls  of 
his  thirty-foot  laboratory :  without  all  this,  aerial 
telegraphy,  such  as  we  know  it,  would  have  been 
an  impossibility. 

And  yet  Hertz  died  before  that  achievement 
had  been  reached.  As  already  stated,  a  civil 
engineer  of  Munich  put  the  question  to  him 
whether  he  thought  telephonic  communication 
would  be  possible  by  means  of  electromagnetic 
waves.  He  answered  in  the  negative,  because 
he  found  the  alternations  of  current  in  the  tele- 
phone too  slow  in  comparison  with  the  period 
of  the  electromagnetic  oscillations.  He  could 
hardly  at  that  time  have  answered  the  question 
otherwise  than  as  he  did ;  for  then  no  sufficiently 
sensitive  means  was  to  hand  for  detecting  elec- 
tromagnetic waves  of  low  intensity. 

As  a  matter  of  fact  the  necessary  apparatus 
for  that  purpose — subsequently  rediscovered  by 


108     THE  STORY  OF  WIRELESS  TELEGRAPHY. 

others  and  as  a  "  Coherer  "  or  "  Radioconductor" 
made  public — had  been  invented  and  turned  to 
practical  account  years  before  Hertz  made  his 
famous  discoveries,  by  Professor  D.  E.  Hughes, 
the  inventor  of  the  micrometer  and  the  printing 
telegraph.  Hughes  had,  by  means  of  this  ap- 
paratus, transmitted  signals  to  a  considerable  dis- 
tance, and  had  recognized  the  nature  and  cause 
of  the  phenomena  by  which  he  had  done  so. 
But  he  had  given  to  the  world  none  of  his  inves- 
tigations, or  the  results  he  had  thereby  attained ; 
although  several  of  the  leading  lights  of  science 
of  the  day  had  witnessed  some  of  the  more  strik- 
ing of  them.  The  facts  only  came  to  light  in 
consequence  of  a  remarkable  forecast  in  regard 
to  wireless  telegraphy  made  by  Sir  William 
Crookes  in  an  article  entitled  Some  Possibili- 
ties of  Electricity,  which  appeared  in  the  Fort- 
nightly Review  for  February,  1892,  and  in  which 
reference  was  made  to  experiments  he  had  wit- 
nessed made  by  Professor  Hughes. 

"  Rays  of  light,"  he  therein  says,  "  will  not 
pierce  through  a  wall,  nor,  as  we  know  only  too 
well,  through  a  London  fog;  but  electrical  vibra- 
tions of  a  yard  or  more  in  wave-length  will  easily 
pierce  such  media,  which  to  them  will  be  trans- 
parent. There  is  revealed  the  bewildering  possi- 
bility of  telegraphy  without  wires,  posts,  cables, 
or  any  of  our  present  costly  appliances.  Granted 
a  few  reasonable  postulates,  the  whole  thing 


CROOKES'S   PREDICTION.  1 09 

comes  well  within  the  realms  of  possible  fulfil- 
ment. At  present  experimentalists  are  able  to 
generate  electric  waves  of  any  desired  length, 
and  to  keep  up  a  succession  of  such  waves  radi- 
ating into  space  in  all  directions.  It  is  possible, 
too,  with  some  of  these  rays,  if  not  with  all,  to 
refract  them  through  suitably  shaped  bodies  act- 
ing as  lenses,  and  so  to  direct  a  sheaf  of  rays  in 
any  given  direction.  Also  an  experimentalist  at 
a  distance  can  receive  some,  if  not  all,  of  these 
rays  on  a  properly  constituted  instrument, 
and  by  concerted  signals,  messages  in  the 
Morse  code  can  thus  pass  from  one  operator  tc 
another. 

"  What  remains  to  be  discovered  is — first, 
simpler  and  more  certain  means  of  generating 
electrical  rays  of  any  desired  wave-length,  from 
the  shortest,  say  a  few  feet,  which  will  easily 
pass  through  buildings  and  fogs,  to  those  long 
waves  whose  lengths  are  measured  by  tens,  hun- 
dreds, and  thousands  of  miles;  secondly,  more 
delicate  receivers  which  will  respond  to  wave- 
lengths between  certain  defined  limits  and  be 
silent  to  all  others  ;  and  thirdly,  means  of  darting 
the  sheaf  of  rays  in  any  desired  direction, 
whether  by  lenses  or  reflectors,  by  the  help  of 
which  the  sensitiveness  of  the  receiver  (appar- 
ently the  most  difficult  of  the  problems  to  be 
solved)  would  not  need  to  be  so  delicate  as  when 
the  rays  to  be  picked  up  are  simply  radiating  into 


110    THE  STORY   OF  WIRELESS  TELEGRAPHY. 

space,  and  fading-  away  according  to  the  law  of 
inverse  squares. 

"  At  first  sight  an  objection  to  this  plan  would 
be  its  want  of  secrecy.  Assuming  that  the  cor- 
respondents were  a  mile  apart,  the  transmitter 
would  send  out  the  waves  in  all  directions,  and 
it  would  therefore  be  possible  for  any  one  living 
within  a  mile  of  the  sender  to  receive  the  com- 
munication. This  could  be  got  over  in  two 
ways.  If  the  exact  position  of  both  sending  and 
receiving  instruments  were  known,  the  rays 
could  be  concentrated  with  more  or  less  exact- 
ness on  the  receiver.  If,  however,  the  sender 
and  receiver  were  moving  about,  so  that  the  lens 
device  could  not  be  adopted,  the  correspondents 
must  attune  their  instruments  to  a  definite  wave- 
length, say,  for  example,  fifty  yards.  I  assume 
here  that  the  progress  of  discovery  would  give 
instruments  capable  of  adjustment  by  turning  a 
screw,  or  altering  the  length  of  a  wire,  so  as  to 
become  receptive  of  waves  of  any  preconcerted 
length.  Thus,  when  adjusted  to  fifty-yard 
waves,  the  transmitter  might  emit,  and  the  re- 
ceiver respond  to,  rays  varying  between  forty- 
five  and  fifty-five  yards,  and  be  silent  to  all 
others.  Considering  that  there  would  be  the 
whole  range  of  waves  to  choose  from,  varying 
from  a  few  feet  to  several  thousand  miles,  there 
would  be  sufficient  secrecy,  for  the  most  inveter- 
ate curiosity  would  surely  recoil  from  the  task  of 


HUGHES'S   RESEARCHES.  Ill 

passing  in  review  all  the  millions  of  possible 
wave-lengths  on  the  remote  chance  of  ultimately 
hitting  on  the  particular  wave-length  employed 
by  those  whose  correspondence  it  was  wished  to 
tap.  By  coding  the  message  even  this  remote 
chance  of  surreptitious  tapping  could  be  ren- 
dered useless. 

"  This  is  no  mere  dream  of  a  visionary  philos- 
opher. All  the  requisites  needed  to  bring  it 
within  the  grasp  of  daily  life  are  well  within  the 
possibilities  of  discovery,  and  are  so  reasonable 
and  so  clearly  within  the  path  of  researches 
which  are  now  being  actively  prosecuted  in  every 
capital  of  Europe,  that  we  may  any  day  expect  to 
hear  that  they  have  emerged  from  the  realms  of 
speculation  into  those  of  sober  fact.  Even  now, 
indeed,  telegraphing  without  wires  is  possible 
within  a  restricted  radius  of  a  few  hundred 
yards,  and  some  years  ago  I  assisted  at  experi- 
ments where  messages  were  transmitted  from 
one  part  of  a  house  to  another  without  interven- 
ing wire,  by  almost  the  identical  means  here  de- 
scribed." 

The  last  sentence  awakened  a  good  deal  of 
curiosity  as  to  who  the  investigator  could  be  who 
had  succeeded  in  telegraphing  without  wires. 
Among  others  whose  interest  was  thus  excited 
was  Mr.  J.  J.  Fahie,  who  had  for  some  time  been 
engaged  on  his  History  of  Wireless  Tele- 
graphy. He  accordingly  wrote  to  Sir  William 


112     THE   STORY   OF   WIRELESS   TELEGRAPHY. 

Crookes  for  some  particulars  of  the  experiments 
alluded  to  in  his  Fortnightly  article,  and  in  an- 
swer to  his  request  was  advised  to  write  to  Pro- 
fessor Hughes,  who  was  by  this  means  induced 
to  give  a  synopsis  of  his  experiments  and  dis- 
coveries. 

The  full  account  as  he  wrote  it,  is  given  in  an 
appendix  to  Mr.  Fahie's  admirable  History 
as  well  as  in  Lodge's  Signaling  through  Space, 
and  may,  in  either  work,  be  seen  by  all  who 
desire  to  consult  it.  But,  as  Hughes's  re- 
searches form  an  important  part  of  the  story  of 
wireless  telegraphy,  it  is  necessary  to  give  here 
a  brief  resume  of  his  investigations,  which  ex- 
tended over  the  years  from  1879  to  1886.  In 
the  former  year,  he  tells  us,  being  engaged  upon 
experiments  connected  with  his  microphone  and 
his  induction  balance,  he  remarked  that  at  times 
he  could  not  get  a  perfect  balance  in  the  induc- 
tion balance,  through  apparent  want  of  insula- 
tion in  the  coils;  but  investigation  showed  him 
that  the  real  cause  was  some  loose  contact  or 
microphonic  joint  excited  in  some  portion  of  the 
circuit.  He  applied  the  microphone  and  found 
that  it  gave  a  current  or  sound  in  the  telephone 
receiver,  whether  the  microphone  was  placed 
direct  in  the  circuit  or  several  feet  away  from 
the  coils  through  which  an  intermittent  current 
was  passing.  After  numerous  experiments  he 
found  that  the  effect  was  caused  by  the  extra 


MYSTERIOUS  WAVES.  113 

current  produced  in  the  primary  coil  of  the  in- 
duction balance. 

Further  researches  proved  that  an  interrupted 
current  in  any  coil  gave  out  at  each  interruption 
such  intense  extra  currents  that  the  whole  atmos- 
phere in  the  room,  or  in  rooms  some  distance 
away,  would  have  a  momentary  invisible  charge, 
which  became  evident  if  a  microphone  joint  was 
used  as  a  receiver  with  a  telephone.  This  led 
him  to  experiment  with  a  view  to  rinding  the 
best  form  of  receiver  for  these  invisible  electric 
waves,  which  evidently  permeated  great  dis- 
tances, and  through  all  apparent  obstacles,  such 
as  walls,  etc.  All  microphonic  contacts  or  joints 
proved  to  be  extremely  sensitive.  Those  formed 
of  a  hard  carbon  such  as  coke,  or  a  combination 
consisting  of  a  piece  of  coke  resting  upon  a 
bright  steel  contact,  were  very  sensitive  and  self- 
restoring;  while  a  loose  contact  between  metals 
was  equally  sensitive,  but  would  cohere,  or  re- 
main in  full  contact  after  the  passage  of  an 
electric  wave. 

After  referring  to  Branly's  "Radioconductor  " 
and  Lodge's  "  Coherer  "  as  rediscoveries  of  his 
microphonic  contacts,  Professor  Hughes  goes  on 
to  say  that  the  most  sensitive  and  perfect  receiver 
he  had  made  did  not  cohere  permanently,  but  re- 
covered its  original  state  instantly,  and  therefore 
required  no  tapping  or  mechanical  aid  to  the 
separation  of  the  contacts  after  momentarily 
8 


114    THE  STORY  OF  WIRELESS  TELEGRAPHY. 

being  brought  into  close  union.  Still  he  soon 
found  that,  while  an  invisible  spark  would  pro- 
duce a  thermo-electric  current  in  the  micro- 
phonic  contacts  (sufficient  to  be  heard  in  the 
telephone  in  its  circuit),  it  was  far  better  and 
more  powerful  to  use  a  feeble  voltaic  cell  in  the 
receiving  circuit,  the  microphonic  joint  then  act- 
ing as  a  relay  by  diminishing  the  resistance  at 
the  contact,  under  the  influence  of  the  electric 
wave  received  through  the  atmosphere. 

Professor  Hughes,  after  stating  that  he  de- 
vised and  experimented  with  numerous  forms  of 
transmitter  and  receiver  in  1879  (particulars  of 
which  were  written  in  books  for  the  purpose), 
goes  on  to  describe  how  he  found  that  very  sud- 
den electric  impulses,  whether  given  out  to  the 
atmosphere  through  the  extra  current  from  a 
coil  or  from  a  frictional  electric  machine,  equally 
affected  the  microphonic  joint,  the  effect  depend- 
ing more  on  the  sudden  high  potential  effect 
than  on  any  prolonged  action.  Thus,  a  spark 
obtained  by  rubbing  a  piece  of  sealing-wax  was 
quite  as  effective  as  a  discharge  from  a  Leyden 
jar  of  the  same  potential — a  fact  independently 
verified  by  Lodge. 

"  The  rubbed  sealing-wax  and  charged  Ley- 
den  jar  had  no  effect  until  they  were  discharged 
by  a  spark,  and  it  was  evident  that  this  spark, 
however  feeble,  acted  upon  the  whole  surround- 
ing atmosphere  in  the  form  of  waves  or  invisible 


MYSTERIOUS   WAVES.  115 

rays,  the  laws  of  which,"  says  Professor  Hughes, 
"  I  could  not  at  the  time  determine.  ...  In 
1879,  while  making  these  experiments  on  aerial 
transmission,  I  had  two  different  problems  to 
solve :  first,  what  was  the  true  nature  of  these 
electrical  aerial  waves,  which  seemed,  while  not 
visible,  to  spurn  all  idea  of  insulation,  and  to 
penetrate  all  space  to  a  distance  undetermined ; 
second,  to  discover  the  best  receiver  that  could 
act  upon  a  telephone  or  telegraph  instrument,  so 
as  to  be  able  to  utilize  (when  required)  these 
waves  for  the  transmission  of  messages.  The 
second  problem  came  easy  to  me  when  I  found 
that  the  microphone,  which  I  had  previously  dis- 
covered in  i877-'78,  had  alone  the  power  of  ren- 
dering those  invisible  waves  evident,  either  in  a 
telephone  or  a  galvanometer,  and  up  to  the  pres- 
ent time  I  do  not  know  of  anything  approach- 
ing the  sensitiveness  of  a  microphonic  joint  as  a 
receiver." 

Professor  Hughes  here  gives  the  names  of  a 
number  of  scientific  men,  including  Sir  W.  H. 
Preece,  Sir  William  Crookes,  Professor  Huxley, 
and  Professor  Dewar,  who  witnessed  some  of  his 
results,  and  then  says  that  they  saw  his  experi- 
ments in  regard  to  aerial  transmission  by  means 
of  the  extra  current  produced  from  a  small  coil 
and  received  upon  a  semi-metallic  microphone, 
the  results  being  heard  upon  a  telephone  in  con- 
nection with  the  receiving  microphone.  The 


Il6     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

transmitter  and  receiver  were  in  different  rooms, 
about  sixty  feet  apart. 

"After  trying  successfully  all  distances 
allowed  in  my  residence  in  Portland  Street," 
Hughes  proceeds,  "  my  usual  method  was  to  put 
the  transmitter  in  operation  and  walk  up  and 
down  Great  Portland  Street  with  the  receiver  in 
my  hand,  with  the  telephone  to  the  ear.  The 
sounds  seemed  slightly  to  increase  for  a  distance 
of  sixty  yards,  then  gradually  diminish,  until  at 
500  yards  I  could  no  longer  with  certainty  hear 
the  transmitted  signals.  What  struck  me  as  re- 
markable was  that  opposite  certain  houses  I 
could  hear  better,  while  at  others  the  signals 
could  hardly  be  perceived.  Hertz's  discovery  of 
nodal  points  in  reflected  waves  (in  i887-'89)  has 
explained  to  me  what  was  then  considered  a 
mystery.  At  Mr.  A.  Stroh's  telegraph  instru- 
ment manufactory,  Mr.  Stroh  and  myself  could 
hear  perfectly  the  currents  transmitted  from  the 
third  story  to  the  basement,  but  I  could  not  de- 
tect clear  signals  at  my  residence  about  a  mile 
distant.  The  innumerable  gas  and  water-pipes 
intervening  seemed  to  absorb  or  weaken  too 
much  the  feeble  transmitted  extra  current  from 
a  small  coil." 

On  February  20,  1880,  Mr.  Spottiswoode,  the 
President  of  the  Royal  Society,  together  with 
Professors  Huxley  and  G.  Stokes,  the  honorary 
secretaries,  called  upon  Professor  Hughes  to  see 


HUGHES   DISCOURAGED.  117 

his  experiments  on  aerial  transmission.  The  ex- 
periments shown  were  very  successful,  and  at 
first  they  seemed  astonished  at  the  results ;  but 
toward  the  close  of  three  hours'  experiments 
Professor  Stokes  said  that  all  the  results  could 
be  explained  by  known  electromagnetic  induction 
effects,  "  and  therefore  he  could  not  accept  my 
view  of  actual  aerial  electric  waves  unknown  up 
to  that  time,  but  thought  I  had  quite  enough 
original  matter  to  form  a  paper  on  the  subject 
to  be  read  at  the  Royal  Society. 

"  I  was  so  discouraged,"  he  continues,  "  at 
being  unable  to  convince  them  of  the  truth  of 
these  aerial  electric  waves  that  I  actually  refused 
to  write  a  paper  on  the  subject  until  I  was  better 
prepared  to  demonstrate  the  existence  of  these 
waves  ;  and  I  continued  my  experiments  for  some 
years,  in  hopes  of  arriving  at  a  perfect  scientific 
demonstration  of  aerial  electric  waves  produced 
by  a  spark  from  the  extra  currents  in  coils,  or 
from  frictional  electricity,  or  from  secondary 
coils." 

Thus,  it  would  appear  that,  through  the  dis- 
couragement of  three  scientific  men,  an  English- 
man was  robbed  of  the  honor  of  being  the  first 
to  announce  the  discovery  of  wireless  tele- 
graphy. Howbeit,  the  distinction  remains  his,  as 
has  been  generally  recognized,  not  only  by  his 
own  countrymen,  but  by  foreign  scientists  as 
well. 


CHAPTER  VIII 

The  imperfect  means  at  Hertz's  command — The  coherer 
and  its  history — Guitard — Varley — Onesti — Professor 
Branly — His  radioconductor — Sir  Oliver  Lodge  and 
the  coherer — His  experiment  at  Oxford  in  1894 — 
Rutherford — Dr.  Muirhead — Captain  Jackson — Pro- 
fessor Bose — Professor  Righi — Lodge's  new  coherer 
— Popoff's  experiments. 

THE  attainment  of  a  "  perfect  scientific  dem- 
onstration of  the  existence  of  aerial  electric 
waves,"  for  which  Hughes  continued  to  work, 
but  unfortunately  failed  to  achieve,  proved  to  be 
an  almost  easy  conquest  to  the  genius  of  Hertz, 
whose  "  strenuous  and  favored  youth  (as  Sir 
Oliver  Lodge  puts  it)  was  surrounded  with  all 
the  influences  that  go  to  make  an  accomplished 
man  of  science."  Truth,  however,  demands  that 
full  recognition  should  be  accorded  to  others 
whose  discoveries  and  inventions  helped  forward 
the  final  achievement  which  was  the  outcome  of 
his  labors.  With  the  imperfect  means  which 
Hertz  had  at  his  command  he  would  probably 
have  held  it  impossible  to  obtain  visible  effects  or 
to  transmit  signals  by  means  of  electric  waves 
that  would  be  audible  at  any  but  a  very  short  dis- 
tance from  their  place  of  origin ;  and  yet  the  dis- 
118 


FIRST  HINT   OF  COHESION.  119 

coverer  of  the  microphone  had  already  actually 
obtained  such  results. 

This  could  not  have  been  done  without  the 
discovery  of  those  wonderful  instruments  which 
are  now  so  well  known  to  the  scientific  world  as 
sensitive  "  contacts,"  "  coherers,"  or  "  radiocon- 
ductors."  Space  forbids  us  to  go  very  deeply 
into  the  history  of  these  various  contrivances,  so 
essential  to  wireless  telegraphy ;  but  some  little 
account  of  them  is  necessary  to  make  the  story 
we  are  telling  complete.  The  principle  of  the 
coherer,  or  the  radioconductor,  lies  in  the  sensi- 
tiveness of  metal  filings  enclosed  in  an  insulating 
tube  to  electric  currents  of  low  potential.  Sir 
Oliver  Lodge  tells  us  that  probably  the  earliest 
discovery  of  cohesion  under  electric  influence 
was  contained  in  an  observation  of  Guitard  in 
1850,  that  when  dusty  air  was  electrified  from  a 
point  the  dust  particles  tended  to  cohere  into 
strings  or  flakes.*  Mr.  S.  A.  Varley  made  a 
practical  application  of  the  same  principle  in  the 
construction  of  his  lightning  protector  for  tele- 
graph apparatus,  which  he  told  the  British  Asso- 
ciation in  1870  had  been  in  use  several  years.  It 
consisted  of  two  thick  metal  conductors  terminat- 
ing in  points,  the  chamber  containing  the  points 
being  loosely  filled  with  a  powder  consisting  of 
carbon  and  a  non-conducting  substance  in  a  min- 
ute state  of  division.  "  The  lighting  finds  in  its 
*  Signaling  through  Space  without  Wires. 


120    THE  STORY  OF  WIRELESS  TELEGRAPHY. 

direct  path  a  bridge  of  powder,  consisting  of 
particles  of  conducting  matter  in  close  proximity 
to  one  another;  it  connects  these  under  the  in- 
fluence of  the  discharge,  and  throws  the  particles 
into  a  highly  incandescent  state.  Incandescent 
matter  .  .  .  offers  a  very  free  passage  to  elec- 
tricity, and  so  the  lightning  discharge  finds  an 
easier  passage  across  the  heated  matter  than 
through  the  coils." 

In  the  action  here  described  we  have  in  rough 
the  principle  of  the  coherer  (Fig.  24) — a  prin- 
ciple  which   was   in- 
dependently       ob- 


FIG.  24.  served    in    1885,    by 

an  Italian  professor,  Signor  Calzecchi-Onesti ; 
who  found  that  iron  filings  contained  in  a  glass 
tube,  placed  between  two  metallic  electrodes, 
became  suddenly  conductive  when  the  electrodes 
were  connected  with  the  two  poles  of  the  second- 
ary circuit  of  a  Ruhmkorff  coil.  This  discovery, 
although  published  in  II  Nuovo  Cimento,  appears 
to  have  attracted  but  little  attention,  and  was  only 
remembered  when,  in  1890,  Professor  E.  Branly, 
of  Paris,  discovered  the  change  that  takes  place 
in  the  conductivity  of  metallic  filings  when  a 
Ley  den  jar  is  discharged  in  its  vicinity.  The 
resistance  of  the  metal  suddenly  falls  from  mil- 
lions of  ohms  to  hundreds.  Its  conductivity  in- 
creases with  the  number  and  intensity  of  the 
sparks.  If,  therefore,  an  electric  battery  be  con- 


BRANLY  COHERER. 


nected  on  to  the  tube  a  current  is  enabled  to  pass 
which  will  produce  action  of  some  sort :  cause  a 
deflection  in  the  galvanometer  needle,  for  in- 
stance, or  put  in  operation  an  electromagnet.  By 
the  latter  proceeding  it  is  possible  to  work  a  reg- 
istering apparatus,  or  to  close  a  local  circuit. 
The  electromagnet  will  then  become  a  relay 
similar  to  those  used  in  ordinary  telegraphy.  It 
is  possible,  therefore,  by  this  means  to  set  free  an 
electric  current  of  any  strength  that  may  be 
desired,  and  thus  to  produce  very  considerable 
results. 

The  annexed  diagram  (Fig.  25)  explains  the 
principle  and  form  of  the  Branly  coherer,  or 
radioconductor,  as  the  in- 
ventor prefers  to  call  it.  A 
vertical  ebonite  cup  contain- 
ing aluminium  powder 
(iron,  brass,  antimony, 
cadmium,  zinc,  or  bismuth 
powder  will  do  as  well)  is 
fixed  between  two  metal 
plates  A  B;  literally  the 
powder  is  in  contact  with  a 
couple  of  rods  C  D,  which 
pass  through  the  sides  of 
the  ebonite  cylinder.  A  and  B  may  be  connected 
to  two  terminals  of  one  of  the  arms  of  the  Wheat- 
stone  bridge,  C  and  D  being  free,  and  vice  versa. 
Whatever  arrangement  be  adopted,  if  a  battery 


FIG.  25. 


122     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

of  a  hundred  cells  be  joined  up  for  a  few  seconds 
with  one  or  other  of  the  pairs  of  terminals,  the 
increase  in  the  conductivity  is  immediately  vis- 
ible in  that  direction,  and  is  found  to  exist  also  in 
the  direction  at  right  angles. 

Sir  Oliver  Lodge  appears  to  have  been  one  of 
the  first  to  recognize  the  importance  of  the 
Branly  coherer,  as  he  called  it,  and  to  apply  it  in 
his  investigations  in  furtherance  of  the  discov- 
eries made  by  Hertz,  using  it  in  place  of  the  re- 


FIG.  26. 

ceiver  or  resonator  of  the  latter.  He  introduced 
certain  improvements,  and  was  thus  enabled  to 
procure  greater  sensitiveness  to  the  electromag- 
netic waves. 

Lodge's  first  form  of  the  instrument  is  shown 
in  Fig.  26.  It  consisted  of  a  glass  or  ebonite 
cylinder  about  seven  inches  in  length  and  half  an 
inch  in  external  diameter,  and  was  fitted  at  the 
ends  with  copper  pistons,  which  could  be  so 
regulated  as  to  press  upon  the  metal  filings  with 
any  degree  of  force  that  might  be  required.  A 
mechanical  "  tapper,"  set  in  motion  either  by  a 
clock-work  arrangement  or  by  a  trembling  elec- 


EXPERIMENTS   AT   OXFORD.  123 

trical  appliance,  was  added  to  shake  back  the 
filings  into  their  normal  non-conducting  condi- 
tion. This  addition,  as  we  shall  see,  was  after- 
ward done  away  with. 

This  form  of  the  radioconductor,  as  Branly 
prefers  to  call  it,  Lodge  exhibited  before  the 
British  Association  at  Oxford  in  1894,  showing 
how  by  means  of  it  signals  could  be  transmitted 
to  a  distance  of  about  150  yards  from  the  source 
of  the  oscillations ;  but,  curious  to  relate,  the  idea 
never  occurred  to  him  that  he  was  experimenting 
with  an  instrument  that  might  be  turned  to  ac- 
count for  long-distance  telegraphy.  Speaking 
of  this  afterward  (in  his  Work  of  Hertz  and  his 
Successors),  he  says:  "Stupidly  enough,  no 
attempt  was  then  made  to  apply  any  but  the 
feeblest  power,  so  as  to  test  how  far  the  disturb- 
ance could  really  be  detected.  Mr.  Rutherford, 
however,  with  a  magnetic  detector  of  his  own 
invention,  constructed  on  a  totally  different  prin- 
ciple, did  make  the  attempt  (June,  1896)  and 
succeeded  in  signaling  across  half  a  mile  full  of 
intervening  streets  and  houses  at  Cambridge." 

In  his  Signaling  through  Space  without 
Wires,  Lodge  further  tells  us  that  Dr.  Alexander 
Muirhead  foresaw  the  telegraphic  importance  of 
this  method  of  signaling  immediately  after  hear- 
ing his  lecture  on  June  i,  1894,  and  arranged  a 
siphon  recorder  for  the  purpose.  Captain  Jack- 
son, also,  of  the  Royal  Navy,  made  experiments 


124    THE   STORY  OF  WIRELESS  TELEGRAPHY. 

for  the  Admiralty  at  Devonport,  and  succeeded 
in  transmitting  signals  from  one  ship  to  another 
without  wires,  prior  to  the  announcement  of 
Marconi's  discovery.  Details  of  these  experi- 
ments, however,  have  not  been  divulged — which 
seems  rather  unfair  to  Captain  Jackson. 

German  investigators  do  not  appear  to  have 
taken  very  readily  to  the  coherer  method  of 
detecting  electric  waves,  and  so  did  not  at  first 
make  such  progress  with  etheric  wave  telegraphy 
as  was  made  in  England  and  elsewhere.  Prof. 
Chunder  Bose,  of  Calcutta,  made  a  series  of 
highly  interesting  experiments,  and  obtained 
results,  especially  in  regard  to  the  production  of 
waves  of  exceedingly  minute  dimensions,  of  the 
highest  importance.  Professor  Righi,  of  Bolo- 
gna, also  entered  upon  a  series  of  exceedingly 
valuable  researches  in  an  optical  direction,  which 
he  has  since  embodied  in  a  treatise  in  Italian, 
entitled  Optice  Elettrica.  These  are  the  more 
interesting  to-day  because  it  was  from  Professor 
Righi  that  Marconi  had  his  first  lessons,  if  not 
his  chief  inspiration,  in  regard  to  the  employ- 
ment of  electromagnetic  waves. 

None  of  these,  however,  had  done  so  much 
with  the  new  power  as  Sir  Oliver  Lodge,  and  it 
is  on  that  account  the  more  astonishing,  when, 
as  it  were,  wireless  telegraphy  was  within  his 
grasp,  that  he  should  have  missed  it — missed  it, 
as  one  imagines,  by  not  having  his  eye  on  the 


THE  NEW  COHERER.  125 

commercial  factor.  In  short,  he  failed  to  appre- 
ciate the  full  magnitude  of  the  power — at  all 
events  from  the  practical  side — which  Hertz's  re- 
searches had  discovered  to  the  world,  and  which 
he  had  done  so  much  to  develop  and  make 
known.  In  especial  was  his  improving  faculty 
manifested  in  regard  to  Branly's  coherer,  which 
he  made  ready  to  Marconi's  hand.  But  he  has 
done  more  than  that.  It  was  seen  almost  from 
the  first  that  the  coherer  in  its  present  form  could 
not  long  remain  as  the  receiver  for  aerial  tele- 
graphy, and  now  the  principal  of  the  Birming- 
ham University  has  produced  an  instrument 
which  bids  fair — certainly  until  a  better  enters 
the  field — to  take  the  place  of  the  old  one. 

The  principle  of  the  new  coherer,  which  is  not 
the  invention  of  Messrs.  Lodge  and  Muirhead,  is 
that  of  two  metallic  bodies  brought  into  contact 
with  a  thin  film  of  mineral  oil  between  them,  the 
impulse  of  the  electric  vibrations  breaking  down 
the  oil  film  and  establishing  a  momentary  co- 
hesion between  the  two  metallic  surfaces,  the  one 
consisting  of  a  steel  disk  and  the  other  of  a 
globule  of  mercury.  It  requires  no  tapper,  but 
is  kept  perpetually  sensitive  by  the  rotation  of 
the  steel  disk,  with  its  razor  edge,  in  close  juxta- 
position to  the  quicksilver  button.  This  beauti- 
ful instrument  is  shown  without  its  metal  case, 
in  Fig.  27,  and  its  construction  in  Fig.  28,  in 
which  a  is  the  rotating  steel  disk,  and  b  the  mer- 


126     THE   STORY   OF   WIRELESS   TELEGRAPHY. 

cury  in  its  trough  d,  with  an  amalgamated  spiral 
of  platinum  wire  c,  connecting  it  to  the  terminal 
or  binding  screw  h,  e  is  a  copper  brush  making 
connection  with  the  steel  disk  a,  through  its  axle 
j,  f  is  a  spring  carrying  a  small  cushion  of  felt  k, 
which  rests  lightly  on 
the  steel  disk  for  the 
purpose  of  keeping  its 
edge  clear  and  free  from 
dust  before  and  after 
contact  with  the  mer- 
cury, g  are  ebonite 
wheels  which  gear  the 
steel  disk  to  the  clock- 
work movement  actu- 
ating the  siphon  r  e  - 
corder,  to  the  side 
whereof  the  metal  case 
containing  the  coherer  is  fixed. 

This  is  one  of  the  most  original  distinguishing 
features  of  the  Lodge- Muirhead  system  of  wire- 
less telegraphy,  which,  like  that  of  Professor 
Fessenden,  of  Alleghany,  like  the  Slaby-Arco 
method,  and  many  others,  embodies  important 
modifications  of,  and  it  may  be  improvements 
upon,  the  Marconi  system,  of  which  it  and  the 
others  are  more  or  less  natural  outcomes. 

Besides  those  already  mentioned,  a  number  of 
other  investigators  devoted  much  time  and 
thought  to  the  line  of  research  wherein  Hertz 


FIG.  27. 


POPOFF'S   COHERER. 


127 


had  won  such  brilliant  results.  Among  these 
we  must  not  omit  to  mention  Professor  Popoff, 
of  the  Military  Academy  of  Cronstadt,  and  his 
apparatus  for  registering  electrical  discharges  in 
the  atmosphere.  He  described  his  invention  in 


FIG.  28. 


FIG.  29. 


a  paper  communicated  to  the  Physico-Chemical 
Society  of  St.  Petersburg  in  1895,  and  from  it 
the  following  particulars  are  taken.  Fig.  29  rep- 
resents his  apparatus,  in  which  A  B  is  a  coherer 
or  radioconductor,  which  together  with  the  elec- 
tromagnet of  a  relay  C,  is  linked  in  the  circuit 
of  a  battery  D.  If  the  contents  of  the  coherer, 
under  the  influence  of  the  electromagnetic  waves, 
be  rendered  conductive,  the  electromagnet  C 
draws  down  its  armature  D.  By  that  means  the 


128     THE  STORY   OF  WIRELESS  TELEGRAPHY. 

contact  E  is  closed,  and  the  current  conducted 
through  the  until  now  open  circuit  F  G  E,  which 
contains  the  electromagnet  of  an  electric  bell. 
This  now  draws  its  armature,  and  the  striker 
hits  the  bell. 

At  the  same  moment  the  circuit  is  interrupted, 
and  the  striker  falls  back  into  its  original  posi- 
tion, in  doing  which  it  shakes  the  coherer  and 
thus  restores  its  resistance.  The  apparatus  there- 
fore, after  announcing  by  the  ringing  of  the  bell 
the  passing  of  the  electric  waves,  automatically 
restores  the  coherer  to  its  normal  condition,  and 
so  puts  it  in  the  position  to  be  again  influenced 
by  the  etheric  waves.  The  relay  actuates  another 
circuit,  not  here  shown,  which  contains  a  Rich- 
ard's register  for  setting  down  in  graphic  signs 
the  electric  perturbations  of  the  atmosphere. 

Popoff  tells  us  that  by  substituting  steel  for 
iron  filings  in  his  coherer,  and  using  a  Hertzian 
exciter  of  thirty  centimeters  diameter,  with  Sie- 
mens and  Halske's  relay,  he  was  able  to  detect 
electric  waves  at  a  distance  of  one  kilometer, 
while,  with  a  Bjerknes  exciter  of  ninety  centi- 
meters diameter,  and  a  more  sensitive  relay,  he 
had  good  results  at  a  distance  of  five  kilo- 
meters. PopofFs  apparatus  shows  some  striking 
analogies  to  that  of  Marconi,  but  more  especially 
in  respect  to  the  use  of  vertical  conductors,  or 
antennae,  as  they  are  sometimes  called,  for  the 
reception  of  the  waves. 


POPOFFS   COHERER  129 

In  a  later  communication  (December  5,  1895) 
Popoff  gives  expression  to  the  confidence  he  has 
of  being  able,  by  means  of  the  electric  waves,  of 
establishing  a  system  of  aerial  telegraphy.  To 
this  end  he  looked  chiefly  to  the  perfecting  of 
his  apparatus  by  a  more  powerful  exciter.  He 
would,  however,  have  attained  the  same  result  if 
he  had  provided  his  transmitter,  as  he  had  done 
his  detector,  with  a  vertical  conductor.  It  re- 
mained for  Marconi,  however,  to  make  this  last 
important  addition. 


CHAPTER  IX 

Gradual  evolution  of  Wireless  Telegraphy  —  Marconi's 
beginnings  —  Studies  at  Bologna  —  Arrival  in  England 
and  introduction  to  Sir  Wm.  Preece  —  His  Indebted- 
ness to  Righi  and  others  —  His  originality  in  seeing 
further  than  others  —  Description  of  his  system  —  His 
oscillator  —  The  coherer  —  The  action  of  the  whole 
apparatus. 

WE  have  now  watched  the  gradual  evolution 
of  well-nigh  all  the  elements  necessary  for  the 
practical  application  of  wireless  telegraphy. 
There  have  been  many  workers  in  the  field,  all 
contributing  their  little  —  as  is  invariably  the  case 
in  such  matters  —  toward  the  as  yet  unrealized, 
and  in  some  instances  undreamed  of,  end,  but  all 
lacking,  as  it  were,  the  broad  synthetic  grasp  to 
comprehend  and  perfect  the  whole.  For  this  it 
required  the 


ejiL_pj[_a_Marcom.  No  one  can  take  from  the 
young  Italian  inventor  the  honor  of  having  been 
the  first  to  see  the  possibilities  lying  hidden  in 
Hertz's  discoveries,  and  at  the  same  time  to  bring 
them  to  a  practical  realization.  Yet  granting 
this  distinction,  justice  requires  that  due  credit 
should  be  given  to  those  who,  by  their  researches 
and  inventions,  paved  the  way,  or,  we  might  say, 
130 


MARCONI'S   START  131 

raised  the  scaffolding  that  enabled  him  to  put  the 
crowning  touch  to  the  whole. 

By  way  of  introduction  to  a  record  of  this 
remarkable  man's  invention,  we  may  say  that 
Guglielmo  Marconi  was  born  near  Bologna, 
Italy,  on  April  25,  1874,  of  Italian-Irish  parent- 
age, and  was  consequently  twenty-two  years  of 
age  when  he  came  to  England  with  fortune  in  his 
hands.  He  had,  as  already  stated,  studied  under 
Professor  Righi  at  the  Bologna  University,  and 
had  made  himself  acquainted  with  all  the  latest 
developments  in  electrical  science,  and  especially 
in  regard  to  their  bearing  upon  telegraphy. 
Righi  was  an  enthusiastic  disciple  of  Hertz  and 
had  contrived  an  improvement  of  his  exciter. 
The  latter's  electromagnetic  waves  were  many 
meters  long,  never,  apparently,  less  than  thirty 
centimeters-;  but  the  Bologna  professor,  by  em- 
ploying small  spheres,  obtained  oscillations  of  2.5 
centimeters.  Even  this  diminution,  was  still  fur- 
ther reduced  by  Professor  Chunder  Bose,  of  Cal- 
cutta, who,  employing  little  pellets  of  platinum, 
was  able  to  produce  vibrations  of  only  six  milli- 
meters in  length. 

This  familiarity  with  Hertz  and  his  work 
created  an  "  atmosphere  "  at  Bologna,  which,  as 
we  may  say,  gave  an  impulse  to  the  study  of 
etheric  phenomena,  and  especially  to  that  cate- 
gory thereof  connected  with  the  researches  of 
Clerk  Maxwell  and  Heinrich  Hertz.  Into  this 


132     THE  STORY  OF  WIRELESS  TELEGRAPHY 

study  Marconi  threw  himself  with  enthusiasm, 
and  one  day  found  himself  wrestling  with  a  new 
idea — the  idea  as  to  whether  these  Hertzian 
waves  could  not  be  utilized  for  the  purpose  of 
realizing  in  an  easier  and  more  complete  manner 
than  had  heretofore  been  done,  the  old  scientific 
dream  of  a  wireless  telegraphy.  He  made  some 
experiments  on  his  father's  estate  near  Bologna, 
and  then  finding  no  one  in  Italy  ready  to  take  up 
his  idea,  set  out  for  his  mother's  homeland  to  try 
his  fortune. 

His  first  step  on  reaching  England  appears  to 
have  been  to  apply  for  a  provisional  protection 
for  his  invention  and  then  to  get  an  introduction 
to  Sir  William  (at  that  time  Mr.)  Preece.  It 
has  been  well  said  by  an  American  writer  that 
Marconi  "  made  no  mistake  when  he  wandered 
into  Mr.  Preece's  office.  He  may  have  heard 
that  no  inventor  with  a  meritorious  idea  or 
machine  ever  met  with  a  discouraging  reception 
from  that  far-seeing,  scientific,  and  practical  offi- 
cial, himself  at  the  very  time  carrying  on  experi- 
ments for  wireless  communication  across  the 
British  waters  on  the  induction  plan."  The 
same  writer  goes  on  to  say  that  "  little  or  nothing 
has  been  said  or  written  about  the  splendid  help 
given  to  the  new  plan  by  the  engineering  branch 
of  the  British  post-office;  but  it  may  be  safely 
assumed  that  to  the  practical  experience  and 
great  skill  of  the  head  and  staff  of  that  depart- 


MARCONI'S  WAVE-EXCITER. 


'33 


ment  belongs  much  of  the  credit  for  the  rapid 
development  of  Marconi's  system." 

Marconi  himself  would  probably  be  one  of  the 
last  to  deny  such  a  statement;  for  like  all  great 
inventions  or  improvements  in  the  arts  and  sci- 
ences, aerial  telegraphy  is  the  outcome  of  the 
labor,  not  of  one  man,  but  of  a  number.  Let  us 
see  to  what  extent  the  steps  had  been  laid  down 
for  Marconi's  advance.  It  hardly  requires  two 
looks  at  the  wave-exciter  (Fig.  30)  described  by 
him  in  his  first  patent  of  June  2,  1896,  and  which 


FIG.  30. 

we  here  reproduce  from  the  English  patent  speci- 
fication, for  any  one  to  see  the  practical  identity 
of  this  apparatus  with  that  of  Professor  Righi, 
as  shown  in  Figs.  31  and  32.  In  both  contriv- 
ances the  waves  arise  from  the  discharge  which 
takes  place  between  the  two  or  more  brass  balls 
or  spheres  by  a  short  spark  springing  across 
through  an  insulating  fluid,  the  requisite  charges 
being  conveyed  to  the  two  spheres  by  the  sparks 
which  leap  betwixt  the  same  and  the  two  outer 
spheres  that  are  connected  with  the  poles  of  a 


FIG.  31. 


134     THE   STORY   OF   WIRELESS   TELEGRAPHY. 

source  of  electricity.    Fig.  31  is  known  as  Righi's 
three-spark  exciter. 

Again,  the  apparatus  sensitive  to  the  electric 
waves  employed  by  Marconi  as  a  receiver  (Fig. 
/  33)  is  no  other  than  the 
v!)_1  2x5§s2  1^9'  filings-tube  of  Professor 
Calzecchi-Onesti,  or  the 
coherer  of  Sir  Oliver 
Lodge.  Further,  the  use 
of  a  relay  for  closing  a  local  circuit,  as 
well  as  the  employment  of  the  clapper  of 
an  electric  bell  for  the  automatic  restora- 
tion of  the  resistance  of  the  filings-tube,  to  say 
nothing  of  the  vertical  conductor,  at  any  rate 
as  part  of  the  receiving  apparatus,  had  already 
been,  as  we  have  seen,  resorted  to  by  other  in- 
vestigators, and  notably  by  Popoff,  who  made 
known  his  method  and 
the  apparatus  by  which 
it  was  operated  in  1895, 
while  Marconi  only  ap- 
plied for  his  patent  in 
June,  1896.  Nor  has 
the  latter  any  better 
title  to  be  considered 
the  originator  of  the 
idea  of  transmitting  messages  to  a  distance  by 
means  of  the  various  apparatus  for  sending  and 
receiving  the  electric  waves  which  he  combined 
together  in  so  comprehensive  a  whole.  The 


MARCONI'S   MERIT. 


135 


thought,  as  we  have  seen,  had  previously  oc- 
curred to  a  number  of  investigators. 

But  when  all  these  allowances  have  been  made, 
it  still  remains  Marconi's  incontestable  merit  that 
he  developed  a  far-seeing  initiative  where  others 
had  not  gone  beyond  timid  projects  or  tentative 


FIG.  33. 

research.  As  Sir  William  Preece  put  it,  "  they 
all  knew  the  egg,  but  Marconi  had  shown  them 
how  to  make  it  stand  on  end."  In  short,  he  car- 
ried forward  into  the  domain  of  practical  reality 
what  had  only  floated  indistinctly  before  the 
minds  of  others,  or  had  served  them  for  modest 
experiments.  This  is  the  calm  and  discriminat- 
ing judgment  of  men  who  have  every  means  at 
command  to  enable  them  to  arrive  at  a  right  con- 
clusion,* and  it  will  no  doubt  be  acquiesced  in  by 
all  who  bring  to  the  consideration  an  impartial 
mind,  including  Marconi  himself.  Judged, 

*  Augusto  Righi  and  Bernhard  Dessau  in  their  work  Die 
Telegraphic  ohne  Draht. 


136     THE   STORY   OF   WIRELESS   TELEGRAPHY. 

therefore,  by  its  practical  results,  Marconi's  ser- 
vice to  science  in  this  matter  resolves  itself  into 
a  victory  over  innumerable  practical  difficulties, 
involving  many  apparently  insignificant  details 
and  minor  improvements,  the  successful  dealing 
with  which  demanded  the  exercise  of  a  gift  that 
has  been  characterized  as  genius  itself. 

Into  all  the  details  distinguishing  Marconi's 
system  we  can  not  pretend  to  enter  here ;  nor  is  it 
necessary  in  a  popular  work  of  this  description. 
Suffice  it,  therefore,  to  give  some  of  its  leading 
features.  For  generating  the  electromagnetic 
waves,  Marconi  in  his  early  experiments,  em- 
ployed, as  we  have  seen,  a  Righi's  oscillator, 
charged  by  a  Ruhmkorff  induction  coil.  In  the 
primary  circuit  of  the  latter,  besides  a  galvanic 
battery  of  a  few  cells  and  an  interrupter,  is  in- 
cluded a  Morse  key,  which  has  to  effect  for 
longer  or  shorter  periods  the  closing  of  the  cir- 
cuit and  the  transmission  of  the  waves  corre- 
sponding to  the  dots  and  dashes  of  the  Morse 
alphabet.  As  interrupter  an  automatic  tapper  is 
employed,  and  in  order  that  it  may  work  prop- 
erly (which  is  not  always  the  case)  a  nickel 
plate  is  fixed  to  the  end  of  a  cylinder  which  is 
kept  revolving  by  means  of  a  small  electrical 
motor  actuated  by  the  current  which  works  the 
coil,  or  by  another  current. 

With  an  induction  coil  capable  of  giving 
sparks  of  about  eight  inches  in  length,  the  two 


CAPACITY  AREAS. 


137 


middle  spheres  of  the  oscillator,  with  diameters 
of  four  inches  each,  are  only  from  ^  to  ^r  of 
an  inch  apart,  while  the  distance  between  each 
of  these  and  the  outer  spheres  is  one  inch.  The 
length  of  the  waves  generated  by  this  apparatus 
is,  according  to  Marconi,  ten  inches. 

In  his  earlier  experiments  the  inventor,  follow- 
ing Righi,  used  an  oscillator  mounted  in  the 
focal  line  of  a  metallic  ». 

reflector,  preferably  of 
brass  or  copper,  whose 
surface  formed  a  para- 
bolical cylinder.  The 
receiver  also  was  sup- 
plied with  a  similar  re- 
flector. But  when  it  was 


FIG.  34. 


desired  to  telegraph  to  great  distances,  Marconi 
found  that  an  arrangement  like  that  represented 
by  t2  t2  (Fig.  34)  produced  better  results  than 
reflectors.  These  are  what  he  calls  his  "  capac- 
ity areas,"  and  consist  of  metal  plates  joined  on 
to  the  oscillator.  Two  similar  plates  also  formed 
part  of  the  receiver.  Marconi's  idea  at  the  time 
was  that  the  carrying  power  of  the  apparatus 
was  increased  with  the  size  of  these  capacity 
areas,  and  the  distance  of  the  same  from  each 
other  and  from  the  earth.  In  the  case  of  sta- 
tions separated  from  each  other  by  elevations  of 
the  ground  or  by  buildings  Marconi  preferred 
the  arrangement  depicted  in  Figs.  35  and  36. 


138     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

Here  a  single  metal  plate  was  hung  by  means  of 
an  insulator  to  a  tall  mast  and  connected  with 
one  end  of  the  exciter  or  the  receiver  respect- 
ively, while  from  the  other  end  a  wire  conducted 
to  earth. 

In  some  cases  these  metal  plates  are  bent  into 
the  form  of  cylinders,  covered  in  at  the  top,  and 


FIG.  35. 


FIG.  36. 


so  hung  on  the  summit  of  the  posts  like  hats. 
The  higher  above  the  earth  these  plates  or  cyl- 
inders are  placed,  the  greater  is  the  distance,  ac- 
cording to  Marconi's  view,  to  which  a  message 
can  be  sent.  In  the  long  run,  however,  he  came 
to  the  conclusion  that  the  deciding  factor  does 
not  lie  in  the  capacity  area  connected  by  means 
of  a  long  wire  with  the  exciter  or  receiver,  but 
in  the  wire  itself;  and  thus  he  finally  did  away 
with  the  plates  altogether  and  employed  for  his 
vertical  conductor  a  long  wire  alone,  which  can 


OSCILLATORS.  139 

be  carried  by  a  mast,  or  when  great  height  is  re- 
quired, by  a  balloon  or  kite. 

Another  form  of  oscillator,  consisting  of 
similar  spheres  mounted  in  an  ebonite  tube,  is 
shown  in  Fig.  37.  The  space  between  the  two 
inner  spheres  was  at  first,  as  in  the  one  already 

FIG.  37. 

described,  filled  with  vaseline  oil  stiffened  with 
solid  vaseline.  The  use  of  oil,  however,  was 
after  a  time  given  up,  experience  showing  that 
it  did  not  offer  the  advantages  which  it  had  been 
thought  it  would,  or  indeed  in  any  way  improve 
the  action  of  the  apparatus  as  regards  the  gener- 
ating of  electromagnetic  waves.  At  the  same 
time  the  apparatus  was  in  other  respects  greatly 
simplified. 

The  most  important  part  of  the  receiver  is  the 
coherer.  If  the  waves  are  received  by  a  reflector 
it  has  to  be  carefully  brought  into  focus.  Mar- 
coni, however,  only  used  a  reflector  in  his  first 
experiments  and  in  special  cases.  Later  it  was 
done  away  with,  and  the  coherer  was  connected 
on  one  side  with  the  vertical  conductor,  and  on 
the  other  side  with  a  wire  conducting  to  earth. 
In  each  case  the  coherer  is  included  in  the  circuit 
of  a  sensitive  relay  and  a  very  weak  battery. 


140     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

The  relay  is  required  to  close  the  circuit  of  a 
stronger  battery,  in  which  the  telegraphic  re- 
ceiver proper,  that  is,  a  Morse  key,  and  an  elec- 
tric tapper  are  inserted  parallel  to  each  other. 
The  latter  serves  to  give  light  taps  to  the  filings- 
tube,  whereby  its  resistance,  lowered  by  the 
waves,  is  again  restored  to  its  normal  condition. 
Marconi  gave  special  care  and  attention  to  the 
perfecting  of  his  coherer.  In  his  hands  it  grew 
not  only  into  an  un- 
commonly sensitive,  but 
also  into  a  very  trust- 
FlG  g  worthy  instrument,  with 

little  of  the  capricious- 
ness  which  characterized  its  original  condition. 
Moreover,  the  dimensions  of  the  coherer  were 
greatly  reduced.  Its  improved  form  is  repre- 
sented in  Fig.  38.  In  a  glass  tube  of  from  four 
to  six  centimeters  in  length  and  from  three  to 
four  millimeters  in  diameter  are  two  closely 
fitting  silver  cylinders,  whose  even  and  parallel 
ends,  turned  the  one  toward  the  other,  are  about 
half  a  millimeter  apart.  The  space  between  the 
two  is  filled  with  metal  filings.  Different  metals 
may  be  employed,  although  Marconi  favors,  as 
best  suited  to  the  purpose,  a  mixture  of  96  per 
cent  of  nickel  to  4  per  cent  of  silver  filings.  The 
latter  are  held  greatly  to  heighten  the  sensitive- 
ness of  the  whole  to  the  Hertzian  waves.  A 
larger  proportion  of  the  silver  filings  still  further 


THE  COHERER.  141 

increases  the  sensitiveness,  but  the  reliableness 
of  the  instrument  is  thereby  impaired.  A  slight 
trace  of  quicksilver  contributes  in  like  manner  to 
heighten  the  effectiveness  of  the  whole. 

The  breadth  of  the  space  between  the  cylinders 
may  vary  within  certain  limits ;  the  wider  it  is 
made  the  larger  must  the  single  filings  be.  In 
general,  however,  a  greater  sensitiveness  is  at- 
tained with  a  narrow  space ;  half  a  millimeter 
proving,  as  a  rule,  to  be  the  most  appropriate 
measurement.  Two  platinum  wires  let  into  the 
glass  tube  and  soldered  to  the  outer  end  of  the 
cylinders  serve  as  external  connections.  Finally, 
by  means  of  a  lateral  addition  the  coherer  is  con- 
nected with  an  air-pump  and  exhausted  to  about 
one-thousandth  of  an  atmosphere. 

The  prepared  coherer  must  still  be  proved  for 
its  sensitiveness,  and  according  to  Marconi  it  is 
only  fitted  for  wireless  telegraphy  when  it 
answers  to  the  inductive  effect  of  an  ordinary 
electric  bell  a  yard  or  two  from  the  tube. 

In  order  to  keep  the  sensitive  tube  in  the  best 
possible  condition,  Marconi  holds  it  to  be  ad- 
visable never  to  allow  the  strength  of  the  cur- 
rent to  exceed  the  limit  of  one  milliampere.  If 
a  stronger  current  be  required  he  considers  it 
better  to  use  several  parallel  tubes,  care  being 
taken  to  have  each  shaken  by  the  tapper;  this 
arrangement,  however,  is  not  quite  so  satisfac- 
tory as  the  single  tube.  When  using  sensitive 


142     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

tubes  of  the  type  here  described  it  is  preferable 
not  to  insert  in  the  circuit  with  it  more  than  one 
cell  of  the  Leclanche  type,  as  a  higher  electro- 
motive force  than  1.5  volt  is  apt  to  pass  a  current 
through  the  tube,  even  when  no  oscillations  are 
transmitted. 

Another  form  of  tube,  however,  provides  for 
working  with  a  higher  electromotive  force.  In 
this  tube,  instead  of  one  space  or  gap  filled  with 
filings,  there  are  several  spaces  separated  by 
plugs  of  tightly  fitting  silver  wire.  Such  a  tube 
will  work  satisfactorily  if  the  electromotive 
force  of  the  battery  in  circuit  with  the  tube  be 
equal  to  about  1.2  volts  multiplied  by  the  number 
of  gaps ;  but  here  also  it  is  well  not  to  allow  a 
current  of  more  than  one  milliampere. 

The  united  action  of  the  different  parts  of  this 
somewhat  complicated  apparatus  is  not  difficult 
to  understand.  When  the  telegraph  instrument 
at  the  sending  station  is  depressed  the  induction 
apparatus  is  set  in  motion,  and  the  discharge  of 
it  generates  electromagnetic  waves  which,  when 
the  oscillation  is  in  the  focal  line  of  a  reflector, 
proceed  in  a  converging  manner  in  a  given  direc- 
tion ;  on  the  other  hand,  when  the  secondary  wire 
of  the  induction  apparatus  leads  to  a  vertical  con- 
ductor they  are  spread  out  from  it  in  all  direc- 
tions. In  the  first  case  the  waves  must  be 
directed  to  the  reflector  of  the  receiver;  in  the 
other  case  a  portion  of  the  oscillations  will  be 


THE    COHERER    CIRCUIT.  143 

taken  up  by  the  vertical  conductor  of  the  re- 
ceiver. In  either  case  they  strike  upon  the  co- 
herer and  reduce  its  resistance. 

In  the  coherer  circuit  a  current  is  thus  set  up 
which  brings  the  relay  into  action ;  the  so-called 
local  battery  is  then  closed  and  sends  a  corre- 
spondingly strong  current  through  the  electro- 
magnet of  the  telegraph  apparatus,  which  draws 
down  its  armature  and  begins  to  give  a  signal. 
At  the  same  time  the  tapper  yields  to  the  pres- 
sure of  its  electromagnet  and  gives  the  filings- 
tube  a  light  tap,  which  at  once  restores  its  resist- 
ance. The  current  in  the  delay  disappears  and 
along  with  it  the  local  current  which  had  set  the 
receiver  and  the  tapper  in  motion. 

If  the  transmitting  station  had  sent  but  a 
momentary  electric  impulse  the  matter  would 
have  ended  there ;  but  if  further  electrical  oscilla- 
tions are  forwarded  to  the  coherer,  the  operation 
of  the  same  begins  afresh  and  the  process  de- 
scribed is  repeated  so  long  as  the  telegraph  key 
is  kept  going,  the  signals  being  reproduced  at  the 
receiving  station  just  as  in  ordinary  telegraphy. 
Of  course  every  transmitting  station  is  also  a 
receiving  station,  the  same  vertical  conductor 
being  enough  for  both  purposes. 

In  addition  to  the  apparatus  already  described 
a  station  for  wireless  telegraphy  must  have  a 
number  of  other  appliances,  some  of  which — too 
much  matters  of  detail  to  mention  here — are  de- 


144    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

scribed  in  Marconi's  patent,  while  others  have 
been  the  outcome  of  later  experiences.  In  his 
first  experiments  the  inventor  connected  two 
strips  of  copper  with  the  coherer  in  order  to 
tune  it  to  the  waves  generated  by  the  oscillations ; 
they  were  attached  to  a  glass  tube  in  the  focal 
line  of  the  receiving  reflector,  but  were  after- 
ward discarded,  Marconi  finding  it  better  to  con- 


FIG.  39. 

nect  the  coherer  on  one  side  with  the  vertical 
conductor  and  on  the  other  with  the  earth. 

Other  alterations  and  improvements  have  for 
object  the  prevention  of  electrical  disturbances 
set  up  by  the  trembler  or  tapper  and  other  ap- 
paratus near  to  or  in  circuit  with  the  tube  from 
themselves  restoring  the  conductivity  of  the 
filings-tube  immediately  after  the  tapper  has  de- 


HIGH  RESISTANCES. 


stroyed  it.  This  purpose  is  effected  by  intro- 
ducing into  the  circuit  at  the  'places  marked  p1 
pz,  q,  s  (in  Fig.  39),  high  resistances  having  as 
little  self-induction  as  possible.  The  action  of 
the  high  resistances  is  that,  while  preventing  an 
appreciable  quantity  of  the  current  from  passing 
through  -them  when  the  apparatus  is  working, 
they  nevertheless  afford  an  easy  path  for  the  cur- 
rents of  high  tension  which  would  be  formed 
at  the  mount  when  the  circuit  was  broken,  and 


FIG.  40. 

thus  prevents  sparking  at  contacts  or  sudden 
jerks  of  currents,  which  would  restore  or  main- 
tain the  conductivity  of  the  sensitive  tube.  Simi- 
lar resistances  or  condensers  are  provided  at 
other  points  for  the  like  purpose,  as,  for  instance, 
to  prevent  the  high  resistance  oscillations  set  up 
across  the  plates  of  the  receiver  by  the  transmit- 
ting instrument,  which  should  pass  through  the 
sensitive  tube,  from  running  round  the  local  bat- 
tery wires  and  thereby  weakening  their  effect  on 
the  sensitive  tube  or  contact. 


146     THE  STORY  OF  WIRELESS  TELEGRAPHY. 

Fig.  40  represents  a  complete  transmitting  and 
receiving  station.  When  working  the  apparatus 
it  is  necessary  either  that  the  local  transmitter 
and  receiver  at  each  station  should  be  at  a  con- 
siderable distance  from  each  other,  or  else  that 
they  should  be  screened  the  one  from  the  other 
by  metal  plates.  The  usual  method  is  to  have 
the  apparatus,  with  the  exception  of  the  sending 
key  and  the  reading  instrument,  enclosed  in  a 
metal 'box  which  is  connected  to  earth. 


CHAPTER  X 

Marconi's  first  experiments  in  England — Trials  on  the 
Bristol  Channel — Also  between  the  Needles  and 
Bournemouth — Experiments  at  Spezia — Valuable  re- 
sults obtained— Professor  Slaby's  investigations  at 
Potsdam  and  elsewhere— Further  experiments  by 
Marconi — Wireless  telegraphy  on  board  the  Royal 
Yacht — Aerial  communications  between  England 
and  France — British  and  French  Associations  for  the 
Advancement  of  Science — Wireless  telegraphy  at  the 
Naval  Maneuvers — Experiments  of  the  Brothers  La- 
carme — Communication  with  balloons — Trials  by 
the  United  States  Navy  Board,  etc. 

MARCONI'S  first  experiments  in  England  took 
place  in  the  General  Post-Office  building  itself, 
under  the  supervision  and  with  the  able  assist- 
ance of  Sir  William  Preece.  These  having 
proved  successful,  his  system  was  submitted  to  a 
more  critical  test  on  Salisbury  Plain,  with  a  clear 
distance  of  two  miles  between  the  sending  and 
receiving  stations.  In  these  experiments  para- 
bolic reflectors  and  resonance  plates  were  used. 

These  trials  having  proved  successful,  Mar- 
coni's apparatus  were  subjected  to  a  more  search- 
ing trial,  along  with  Preece's  own  method.  The 
experiments  took  place  between  Lavernock  Point 
and  Flatholm  (3.3  miles),  and  also  between 

147 


148     THE   STORY   OF   WIRELESS   TELEGRAPHY. 

Lavernock  Point  and  Brean  Down  (8.7  miles) 
on  the  opposite  side  of  the  Bristol  Channel. 
Here  the  reflectors  were  done  away  with  and 
vertical  wires  employed  in  their  stead.  The 
receiving  station  was  fixed  at  Lavernock  Point, 
twenty  yards  above  the  level  of  the  sea.  A  mast 
thirty  yards  high  was  erected  and  on  the  top  of 
it  placed  a  cylindrical  cap  made  of  zinc,  two  yards 
long  and  one  in  diameter.  Connected  with  this 
cap  was  a  copper  wire  leading  to  one  electrode  of 
the  coherer,  the  other  electrode  being  attached 
to  a  wire  that  descended  into  the  sea. 

The  sending  apparatus  was  placed  on  Flat- 
holm  where  the  vertical  wire  and  the  zinc  cap 
resembled  those  at  Lavernock  Point.  A  Ruhm- 
korff  coil  giving  twenty-one  inch  sparks,  with  an 
eight-cell  battery,  was  used  for  generating  the 
Hertzian  waves.  After  some  experiments  had 
been  made  with  Preece's  method  (already  de- 
scribed), which  were  entirely  successful,  Mar- 
coni's apparatus  was  put  to  the  test.  At  first  the 
trials  were  anything  but  satisfactory — indeed 
they  were  little  short  of  utter  failures.  Next 
day,  however,  May  12,  the  vertical  wire  having 
been  lengthened  by  twenty  yards,  the  results, 
though  still  unsatisfactory,  were  better ;  while  on 
the  1 3th,  when  the  receiving  apparatus  was  taken 
down  from  the  cliff  to  the  beach  and  a  further 
length  of  wire  added,  the  success  achieved  was 
beyond  doubt. 


TRIALS   AT  SPEZIA.  149 

The  experiments  which  followed  betwixt 
Lavernock  Point  and  Brean  Down  were  equally 
satisfactory,  as  were  also  similar  trials  that  took 
place  in  the  following  November  between  the 
Needles,  Alum  Bay,  Isle  of  Wight,  and  Madeira 
House,  Bournemouth. 

These  experiments  attracted  so  much  attention 
that  the  Italian  Ministries  of  War  and  Marine 
caused  a  series  of  trials  to  be  made  at  Spezia 
between  July  n  and  July  18,  1897,  under  Mar- 
coni's direction.  The  first  three  days  were 
devoted  to  trials  on  land,  when  excellent  results 
were  obtained  at  a  distance  of  3.6  kilometers. 
On  the  I4th  the  scene  of  operations  was  trans- 
ferred to  the  water.  The  sending  apparatus, 
which  was  installed  in  a  tent  upon  a  tongue  of 
land  near  the  arsenal  of  St.  Bartholomew  on  the 
eastern  side  of  the  Gulf  of  Spezia,  consisted  of 
an  oscillator  with  two  central  spheres  of  ten 
centimeters  and  two  outer  spheres  of  five  centi- 
meters diameter  and  an  induction  coil  with 
sparks  twenty-five  centimeters  in  length,  sup- 
plied by  an  accumulator  battery.  The  vertical 
wire  was  twenty-six  yards  in  length  and  ter- 
minated in  a  zinc  plate. 

The  receiving  apparatus  was  set  up  on  a  tug- 
boat, and  had  a  vertical  wire  running  to  the  top 
of  a  mast  sixteen  yards  high  and  terminating  in 
a  zinc  plate,  while  another  wire  led  from  the 
coherer  into  the  water.  Transmission  was  sue- 


150    THE  STORY   OF  WIRELESS  TELEGRAPHY. 

cessful  up  to  four  kilometers.  On  July  15  the 
experiments  were  continued  with  the  same  ap- 
paratus, only  the  "  antenna  "  of  the  sender  was 
lengthened  to  thirty  yards.  At  first  the  trials 
were  unsuccessful,  the  receiver  giving  signals, 
through  the  presence  of  thunder-clouds,  before 
the  transmitter  had  began  to  work.  When, 
however,  these  atmospheric  disturbances  had 
ceased  and  the  tug  began,  as  on  the  previous 
day,  to  move  out  further  and  further  from  the 
sending  station,  the  signals  continued  intelligible 
until  a  distance  of  5.5  kilometers  had  been 
reached.  But  when  the  vessel  became  hidden 
from  the  sending  station  by  a  stretch  of  land  the 
signals  stopped  altogether. 

On  the  1 6th  the  tug-boat  kept  the  sending  sta- 
tion continually  in  sight,  and  up  to  a  distance  of 
thirteen  kilometers  the  messages  sent  were  leg- 
ible. When,  however,  the  steamer  turned  about 
and  began  to  make  its  way  back,  it  seemed  as 
though  the  receiver  had  lost  some  of  its  sensi- 
tiveness, and  only  at  a  much  less  distance  than 
before  were  the  signals  intelligible. 

These  unfavorable  results  were  attributable  in 
part  to  the  fact  that  the  vertical  wires  of  the 
two  stations  did  not  rise  perpendicularly,  but 
obliquely  and  with  irregular  bends.  When  the 
tug  was  steaming  outward  they  were  fairly 
parallel  to  each  other,  but  on  the  return  journey 
they  were  in  a  much  less  favorable  position  the 


UNFAVORABLE   RESULTS.  151 

one  to  the  other.  Another  unfavorable  circum- 
stance was  that  in  steaming  back  the  mast  carry- 
ing the  "  antenna "  came  betwixt  the  sending 
station  and  the  receiving  wire,  and  must  have 
received  or  turned  aside  some  of  the  electromag- 
netic energy  which  would  otherwise  have  reached 
the  coherer. 

These  influences  entered  still  more  unfortu- 
nately into  the  concluding  experiments  on  July 
17  and  1 8.  The  length  of  the  vertical  wire 
at  the  transmitting  station  was  increased  to 
thirty-four  meters,  while  that  connected  with  the 
received  apparatus,  placed  on  these  days  on  the 
ironclad  S.  Martino,  was  at  first  seventeen 
meters  and  then  twenty-eight  meters  in  length. 
On  the  outward  run  messages  were  successfully 
transmitted  up  to  a  distance  of  eighteen  kilo- 
meters ;  but  on  the  return  journey,  when  the 
masts  and  funnels  of  the  steamship  came  between 
the  receiving  wire  and  the  sending  station,  the 
same  unfavorable  results  were  experienced  as  on 
the  previous  day,  and  in  a  more  marked  degree. 

The  cause  of  these  unfortunate  appearances 
was  not  to  be  mistaken.  On  the  ironclad  the 
straight  course  between  the  sending  station  and 
the  receiving  wire  was  barred  by  a  still  greater 
mass  of  metal  than  on  the  tug.  On  the  other 
hand  the  placing  of  the  coherer  and  its  auxiliary 
apparatus  on  the  ironclad  appeared  to  have  little 
influence  upon  the  transmission ;  the  legibility, 


152     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

although  not  so  good  as  usual,  was  still  passable, 
even  when  the  coherer  was  installed  beneath  the 
armor-plated  deck,  where  it  was  surrounded  on 
almost  every  side  by  thick  masses  of  metal.  Yet 
in  these  experiments  again  it  was  found  impos- 
sible to  get  signals  through  when  the  line 
between  the  vessel  and  the  sending  station  was 
broken  by  a  point  of  land  or  by  an  island. 

In  these  investigations  an  important  consid- 
eration, which  Marconi  had  previously  observed, 
and  the  law  in  regard  to  which  he  now  believed 
he  had  confirmed,  was  the  influence  of  the  height 
of  the  vertical  conductor  on  the  distance  to  which 
transmission  can  be  effected.  According  to 
Marconi's  view  the  limit  of  transmission  in- 
creases with  the  square  of  the  height  of  the  wire. 
Thus  if  the  height  of  the  vertical  wire  at  both 
stations  were  doubled  the  limit  of  transmission 
would  be  quadrupled.  Hence  it  having  been 
ascertained  that  a  wire  twenty  feet  high  is  suffi- 
cient to  carry  a  message  a  mile,  a  simple  calcu- 
lation gives  the  height  that  would  be  required  to 
telegraph  to  a  distance  of  twenty  miles,  and  so 
on.  But  whether  the  law  be  so  simple  as  that  or 
not  (which  there  is  reason  to  doubt),  it  at  any 
rate  appears  to  hold  good  for  water  only.  On 
land,  especially  where  there  are  elevations  of  the 
ground,  or  buildings  or  trees,  a  greater  length 
of  vertical  wire  is  required  for  a  given  distance 
than  when  the  telegraphing  is  done  over  a  simple 


SLABY'S   EXPERIMENTS.  153 

water  surface.  Hertz  found  that  the  electro- 
magnetic waves  went  through  doors  and  walls 
and  indeed  through  all  non-conducting  sub- 
stances, being  only  stopped  by  conductors ;  but 
the  rule  has  its  exceptions  in  actual  practice — 
that  is,  when  the  wood  of  doors  is  translated 
into  trees,  and  so  forth. 

These  observations   were  confirmed  by   Pro- 


FlG.  41. 

fessor  Slaby,  of  Charlottenberg.  Slaby  had  wit- 
nessed the  trials  at  Lavernock  Point,  and  had 
been  so  struck  by  them  that  on  his  return  to  Ger- 
many he  set  about  making  similar  experiments 
himself.  These  took  place  first  between  his  own 
laboratory  and  a  neighboring  house,  and  then  in 
the  grounds  of  the  Imperial  Palace  at  Potsdam. 
His  apparatus  was  not  essentially  different  from 
Marconi's ;  although,  having  found  the  latter's 


154     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

coherer  too  sensitive  to  atmospheric  disturb- 
ances, he  used  coarser  filings.  His  sending  ap- 
paratus was  set  up  in  the  portico  of  the  church 
at  Sakrow,  as  shown  in  Fig.  41,  the  vertical  con- 
ductor being  suspended  from  the  end  of  a  pole 
on  the  top  platform  of  the  tower,  twenty-three 
meters  above  the  ground,  while  the  receiving 
apparatus  was  stationed  on  the  bridge  at  Glien- 
ick,  1.6  kilometers  distant.  Transmission  was 
perfect  except  when,  in  order  to  protect  the  send- 
ing apparatus  from  the  rain,  it  was  pushed  too 
far  within  the  entrance  of  the  church,  thereby 
making  it  necessary  to  run  the  wire  for  a  short 
distance  parallel  with  the  earth.  Similarly  un- 
favorable results  followed  where  trees  stood  in 
front  of  or  too  near  the  transmitting  wire. 

According  to  Slaby  the  vertical  conductors  of 
both  stations  should  be  in  sight  the  one  of  the 
other.  Even  the  sail  of  a  boat  or  the  smoke  of  a 
small  steamer  coming  between  the  two  stations, 
or  even  a  strong  wind,  were  sufficient  at  times  to 
turn  the  signals  aside.  He  holds,  too,  that  for 
distinctness  of  transmission  the  two  conductors 
should  be  of  equal  height.  As  at  the  Spezia 
trials,  so  Slaby,  at  Berlin,  found  that  any  consid- 
erable unevenness  of  the  ground  between  the  two 
stations  influenced  the  signaling. 

In  October,  1897,  Professor  Slaby  instituted  a 
series  of  experiments  on  a  still  larger  scale.  On 
this  occasion  his  receiving  apparatus  was  set  up 


CAPTIVE  BALLOONS.  155 

on  the  shooting-range  at  Schoneberg,  near  Ber- 
lin, while  the  sending  station  was  on  the  military 
parade  ground  at  Rangsdorf,  twenty-one  kilo- 
meters distant.  Captive  balloons,  at  a  height  of 
from  200  to  280  meters,  were  employed  in  place 
of  masts  for  carrying  up  the  wire  conductors. 
At  first  it  was  thought  that  the  steel  ropes  which 
held  the  balloons  might  serve  as  conductors ;  but 
no  good  came  of  the  attempt ;  and  it  was  only 
when  a  copper  wire  was  employed  independently 
of  the  steel  tethering  rope,  that  faultlessly  dis- 
tinct messages  were  received.  Perfect  trans- 
mission, however,  was  sometimes  prevented  by 
electrical  disturbances  in  the  atmosphere,  at 
which  times  it  was  found  to  be  extremely  danger- 
ous to  work  the  instruments. 

It  is  worthy  of  note  that  the  distance  at  which 
Professor  Slaby  got  successful  signals  was  the 
longest  which  had  at  that  time  been  attained. 
These  experiments  were  published  by  Professor 
Slaby  in  a  work  entitled  Funken  Telegraphic 
(i.  e.  Spark  Telegraphy).  Many  of  the  lead- 
ing achievements  in  aerial  telegraphy  which  fol- 
lowed upon  the  formation  of  the  "  Wireless  Tele- 
graph and  Signal  Company,"  formed  to  work 
Marconi's  patent,  will  be  well  within  the  recol- 
lection of  most  people,  and  need  not  be  referred 
to  here,  except  in  so  far  as  they  brought  out  or 
emphasized  new  developments  in  connection  with 
aerial  telegraphy. 


156    THE  STORY   OF  WIRELESS   TELEGRAPHY. 

In  July,  1898,  on  the  occasion  of  the  Kings- 
town Regatta,  the  Flying  Huntress,  which  was 
provided  with  a  sending  apparatus,  followed  the 
races  and  reported  the  results  through  a  receiv- 
ing station  set  up  on  shore  for  the  Dublin  Daily 
Express.  This  was  regarded  at  the  time  as  a 
great  achievement;  but  a  still  more  surprising 
exhibition  of  the  power  of  the  new  telegraphy 
was  given  in  the  following  month,  when  for  six- 
teen days  the  royal  yacht  Osborne,  with  the 
King,  then  Prince  of  Wales,  on  board,  was  kept 
in  uninterrupted  communication  with  Osborne 
House.  The  vertical  conductor  on  board  had  a 
height  of  eighty-three  feet  and  the  pole  at  Lady- 
wood  Cottage  100  feet. 

The  royal  yacht  was  usually  anchored  in 
Cowes  Bay,  nearly  two  miles  from  Osborne 
House;  but  on  August  12  she  ran  out  to  the 
Needles,  and  telegraphic  communication  was 
kept  up  with  Osborne  until  off  Newton  Bay,  a 
distance  of  seven  miles,  although  the  two  places 
were  separated  from  each  other  by  considerable 
elevations  of  ground.  During  the  same  month 
successful  communications  were  carried  on 
between  Alum  Bay  and  the  Haven  Hotel,  Poole, 
a  distance  of  eighteen  miles. 

Important  experiments  were  conducted  in 
March,  1899,  between  the  South  Foreland  Light- 
house and  a  station  fixed  up  at  Wimereux,  on 
the  French  coast,  near  Boulogne.  The  two 


MESSAGES  IN   FOG  AND  RAIN.  157 

places  are  forty-five  kilometers  distant  the  one 
from  the  other.  The  vertical  conductors,  which 
were  at  first  forty-five  meters  in  height,  but 
afterward  reduced  to  thirty-seven  meters,  con- 
sisted of  cables  formed  of  seven  strands  of  cop- 
per wire  0.9  millimeters  in  thickness  with  gutta- 
percha  insulation.  Aloft  each  cable  terminated 
in  a  spiral,  which  was  fastened  to  its  mast  by 
means  of  two  ebonite  cylinders. 

Signals  were  also  exchanged  between  the 
South  Foreland  and  the  East  Goodwin  Light- 
ship, which  was  provided  with  a  vertical  con- 
ductor twenty-four  meters  in  height,  as  well  as 
with  the  dispatch  boat  Ibis,  and  the  transport 
La  Vienne,  with  conductors  of  twenty-two  and 
thirty-one  meters  length  respectively. 

Fog,  rain,  and  storm  notwithstanding,  mes- 
sages were  sent  to  and  fro  between  the  South 
Foreland,  and  between  the  latter  place  and  the 
East  Goodwin  Lightship,  without  the  least  diffi- 
culty. The  same  success  attended  the  experi- 
ments between  the  land  stations  and  the  Ibis  and 
La  Vienne,  whether  they  lay  at  anchor  or  were 
moving  from  place  to  place.  The  greatest  dis- 
tance at  which  messages  were  exchanged  be- 
tween one  of  these  vessels  and  the  South  Fore- 
land was  fifty-two  kilometers.  If  the  direct  line 
between  the  two  signaling  stations  happened  to 
be  broken  by  intervening  objects  the  signals  were 
naturally  legible  at  a  less  distance.  Neverthe- 


158     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

less  the  Ibis,  with  an  antenna  of  twenty-two 
meters,  was  able  to  exchange  messages  with 
Wimereux,  whose  vertical  conductor  on  the  oc- 
casion of  this  experiment  had  a  height  of  forty- 
five  meters,  although  the  direct  line  between  the 
two  stations  (nineteen  kilometers  in  length)  was 
broken  by  the  lofty  promontory,  Cape  Gris-Nez. 
In  the  month  of  September,  1899,  the  British 
Association  for  the  Advancement  of  Science  held 
its  annual  meeting  at  Dover,  while  at  the  same 
time  the  "  Association  Frangaise  pour  1'Avance- 
ment  des  Sciences  "  met  at  Boulogne.  An  ap- 
paratus (as  shown  facing  title)  was  set  up  in 
the  town  hall  at  Dover,  and  messages  between 
that  place  and  Wimereux  were  successfully  sent 
and  received,  despite  the  masses  of  cliff  that 
interpose  between  the  two  places.  Wimereux 
was  also  put  into  direct  communication  with  a 
Marconi  station  at  Dovercourt,  near  Harwich, 
and  with  Chelmsford.  Both  places  are  136 
kilometers  from  Wimereux ;  the  line  between  the 
last-named  place  and  Dovercourt,  however,  is 
entirely  over  the  sea,  except  at  one  point,  where 
it  is  cut  by  the  point  of  the  North  Foreland, 
while  the  distance  between  Wimereux  and 
Chelmsford  is  half  over  land,  and  therefore 
offered  less  favorable  conditions  for  telegraphy 
without  wires.  Nevertheless  the  experiments, 
for  which  conductors  forty-five  meters  in  height 
were  used,  were  entirely  successful. 


TRIALS  IN    1899.  159 

A  series  of  exceedingly  interesting  trials  of  the 
Marconi  system  at  sea  was  conducted  during  the 
British  naval  maneuvers  of  the  same  year 
(1899).  Three  ships  were  fitted  up  with  the 
apparatus:  the  Alexandra  (flag-ship),  and  the 
cruisers  Juno  and  Europa.  The  two  latter  ex- 
changed signals  at  a  distance  of  sixty  nautical 
miles,  the  Juno  and  the  Alexandra  at  a  distance 
of  forty  nautical  miles.  Signals  were  obtained 
at  a  still  greater  distance  (seventy-four  nautical 
miles),  but  the  former  were  held  at  the  time  to 
indicate  more  truly  the  limit  of  clearness  and 
legibility.  The  special  point  of  interest  in  these 
experiments  consisted  in  the  fact  that,  in  con- 
sequence of  the  rotundity  of  the  earth,  a  great 
mass  of  water  intervened  between  the  ships,  and 
hence  the  electric  waves  must  either  go  right 
through  it  or  find  their  way  over  its  surface. 
Sir  Oliver  Lodge,  I  believe,  holds  that  the  elec- 
tric oscillations  leap  from  wave  to  wave. 

The  experimenters  in  the  field  of  wireless  tele- 
graphy had  by  this  time  become  almost  number- 
less, and  scarcely  a  week  passed  without  one 
success  or  another  being  announced.  One  of  the 
most  interesting  of  these  trials  was  that  of  the 
brothers  Lecarme,  who  set  up  apparatus  at  Cha- 
mounix  and  at  the  observatory  on  the  summit  of 
Mont  Blanc,  erected  by  Vallot.  The  importance 
of  these  experiments  lies  not  so  much  in  the  dis- 
tance reached  (12  kilometers  only),  as  in  the 


l6o     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

difference  of  elevation,  between  the  two  points, 
Chamounix  being  1,000  meters  and  Mont  Blanc 
4,350  meters  above  the  sea-level  The  experi- 
ments were  completely  successful,  being  inter- 
rupted neither  by  clouds  nor  by  atmospheric  dis- 
turbances ;  but  at  night,  when  Chamounix  was 
electrically  lighted,  wave  telegraphy  became  an 
impossibility. 

The  transmission  of  messages  from  the  earth 
to  balloons  by  wire  telegraphy  was  made  the  sub- 
ject of  experiment  in  the  Austrian  and  French 
armies  during  the  same  year  (1899).  The  send- 
ing station  in  each  case  was  on  terra  firma,  the 
vertical  conductor,  whose  length  in  the  Austrian 
trials  was  150  and  in  the  French  forty  meters, 
being  carried  up  by  captive  balloon.  The  an- 
tennae of  the  receiving  apparatus,  which  in  the 
first  case  was  twenty  meters  and  in  the  second 
fifty  meters  long,  hung  from  the  balloon,  in  the 
basket  whereof  the  apparatus  was  placed.  The 
greatest  distance  to  which  signaling  could  be 
effected  by  the  French  experimenters  was  six 
kilometers,  the  balloon  being  at  the  time  200 
meters  from  the  ground.  The  Austrian  officers, 
in  consequence  (it  was  thought)  of  better 
weather  conditions  and  a  longer  conductor,  suc- 
ceeded in  transmitting  messages  to  a  distance  of 
ten  kilometers  with  the  balloon  at  a  height  of 
i, 600  meters.  Similar  experiments  had  already 
taken  place  in  the  German  army ;  but  nothing 


REPORTS  OF  AN  "AMERICAN"  YACHT  RACE.     l6l 

very  explicit  was  made  known  respecting  them 
further  than  that  signals  were  successfully  trans- 
mitted from  the  earth  to  the  balloon  when  the 
latter  was  forty-five  kilometers  from  the  sending 
station. 

In  October,  1899,  the  progress  of  the  yachts 
in  the  international  race  between  the  Columbia 
and  Shamrock  was  successfully  reported  by 
aerial  telegraphy,  as  many  as  4,000  words  having 
been  (as  is  said)  despatched  from  the  two  ship 
stations  to  the  shore  stations.  Immediately 
afterward  the  apparatus  was  placed  by  request 
at  the  service  of  the  United  States  Navy  Board, 
and  some  highly  interesting  experiments  fol- 
lowed under  Marconi's  personal  supervision. 
The  instruments  were  set  up  on  board  the  cruiser 
New  York  and  the  battleship  Massachusetts, 
and  although  those  vessels  were  not  provided 
with  all  the  improvements  which  had  then  been 
made,  the  Massachusetts  was  nevertheless  suc- 
cessful in  transmitting  intelligence  to  the  New 
York  at  a  distance  of  thirty-five  miles.  When 
messages  were  sent  the  other  way  only  about 
half  the  distance  was  reached.  On  another 
occasion  the  very  opposite  occurred.  Neverthe- 
less the  report  of  the  Navy  Board  was  in  gen- 
eral favorable,  and  recommended  the  adoption 
of  the  system  "  on  all  vessels  in  the  navy,  in- 
cluding torpedo-boats,  and  small  vessels,  as 
patrols,  scouts,  and  despatch-boats." 


1 62     THE   STORY  OF  WIRELESS  TELEGRAPHY. 

In  the  month  of  March,  1900,  the  Marconi 
system  was  adopted  by  the  Nordeutscher  Lloyd 
Steamship  Company,  and  by  agreement  with 
that  company  apparatus  was  installed  in  the 
Borkum  Riff  Lightship  and  in  Borkum  Light- 
house, as  also  on  board  the  L.M.S.  Kaiser 
Wilhelm  der  Grosse.  From  the  commence- 
ment of  the  service  about  the  middle  of 
May  until  the  end  of  the  year  the  station  on  the 
lightship  received  582  telegrams  from  passing 
ships,  fifty-three  telegrams  were  sent  from  the 
lightship  to  passing  vessels,  while  twenty  tele- 
grams went  from  ships  direct  to  the  lighthouse 
station,  totaling  in  all  to  upward  of  8,000  words. 

It  need  hardly  be  pointed  out  what  an  im- 
portant service  to  commerce  this  represents. 
But  the  immense  utility  of  the  system  was  shown 
on  more  than  one  occasion  during  the  same 
period  in  a  strikingly  dramatic  manner.  The 
Borkum  Riff  Lightship,  for  instance,  one  day  at 
the  height  of  a  storm  was  torn  from  its  anchors 
and  driven  out  to  sea,  and  the  probability  is 
that  all  on  board  would  have  been  lost  but  for 
the  fact  that  they  were,  by  the  Marconi  system, 
enabled  to  send  a  report  to  Borkum  of  what  had 
happened. 

In  July  of  the  same  year  (1900)  a  contract 
was  entered  into  with  the  British  Admiralty  for 
the  installation  of  the  Marconi  apparatus  on 
twenty-six  of  H.  M.  ships  and  at  six  coast  sta- 


SERVICES  TO  COMMERCE.  163 

tions.  The  contract  contained  the  condition  that 
the  apparatus  should  render  possible  the  ex- 
change of  signals  between  two  ships  of  which  the 
one  should  be  stationed  at  Portland  and  the  other 
at  Portsmouth,  sixty-two  miles  distant  and  sepa- 
rated from  the  former  place  by  the  Devonshire 
hills — a  condition  which  was  satisfactorily  ful- 
filled. 


CHAPTER  XI 

The  American  Navy  Board  and  "interference" — Wireless 
telegraphy  experiments  at  Calvi,  Corsica — Syntony 
imperfectly  attained — Sir  Oliver  Lodge  and  syntony 
— Signals  received  at  St.  John's  Newfoundland, 
from  Cornwall — The  influence  of  sunlight  upon  send- 
ing wires — Experiments  on  the  Carlo  Alberta — The 
apparatus  on  board  and  at  Poldhu — Report  on  the 
results — Marconi's  detector — Criticisms  on  the  re- 
port— Tapping  the  messages — Syntony  again — 
Achievements  of  transatlantic  telegraphy  without 


IN  the  report  of  the  United  States  Navy 
Board,  already  referred  to,  reference  is  made  to 
a  very  important  point  in  regard  to  aerial  tele- 
graphy. "  When,"  says  the  report,  "  two  trans- 
mitters are  sending  at  the  same  time,  all  the  re- 
ceiving wires  within  range  receive  the  impulses, 
and  the  tapes  although  unreadable,  show  unmis- 
takably that  such  double  sending  is  taking  place. 
In  every  case,  under  a  great  number  of  varied 
conditions,  the  interference  was  complete.  Mr. 
Marconi,  although  he  stated  to  the  board,  before 
these  attempts  were  made,  that  he  could  prevent 
interference,  never  explained  how,  nor  made  any 
attempt  to  demonstrate  that  it  could  be  done." 

!64 


ONE   OF  THE  WEAK  POINTS.  165 

This  criticism  goes  to  the  root  of  one  of  the 
weak  points  of  wireless  telegraphy.  A  great 
deal  has  been  made  of  the  possibility,  by  syntony, 
of  so  "  tuning "  the  transmitter  to  the  receiver 
as  to  render  a  message  going  from  one  to  the 
other  not  only  illegible  to  a  receiver  not  tuned 
to  the  proper  pitch  or  key,  but  inappreciable 
thereto.  In  other  words,  if  we  have  understood 
Marconi  aright,  he  entertains  the  belief  that  he 
can  send  a  signal  in  such  a  way  that  all  receivers 
not  specially  tuned  to  the  sending  instrument 
shall,  as  we  may  say,  be  deaf  thereto.  Up  to  the 
present,  however,  so  far  as  we  are  aware,  little 
or  nothing  has  been  done  to  justify  the  promise. 

One  of  the  most  important  series  of  experi- 
ments instituted  by  the  Marconi  International 
Marine  Communication  Company  was  that  car- 
ried out  between  Biot  on  the  coast  of  Provence, 
and  Calvi,  Corsica,  the  two  stations  being  175 
kilometers  apart.  According  to  the  testimony  of 
witnesses,  the  results  obtained  were  most  satis- 
factory. Messages  passed  to  and  fro  in  a  most 
faultless  manner;  the  dots  and  dashes  of  the 
Morse  alphabet  were  all  clearly  distinct  one  from 
another ;  but  the  much-desired,  and  apparently 
greatly  aimed  at,  syntony,  was  only  imperfectly 
attained.  Sometimes  the  receiving  apparatus 
would  innocently  pick  up  and  register  messages 
that  were  being  exchanged  between  battle-ships 
thirty  kilometers  distant. 


1 66     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

The  same  thing  has  happened  again  and  again, 
and  we  are  in  consequence  driven  to  the  con- 
clusion that,  though  resonance  or  syntony  has 
much  to  do  with  the  clear  transmission  of  mes- 
sages by  the  aerial  path,  it  has  not  yet  been 
found  possible  by  its  means  to  prevent  interfer- 
ence or  the  interception  of  messages.  Indeed,  it 
is  an  open  secret  that  the  despatches  going  to 
and  from  Poldhu  are  read  on  the  post-office  in- 
struments at  Penzance,  as  well  as  Porthcurno, 
the  Eastern  Telegraph  Company's  station. 

So  far,  therefore,  it  may  be  said  that  the  at- 
tempt to  individualize  signals  by  resonance  or 
syntony  has  not  proved  a  conspicuous  success. 
Whether  such  will  always  be  the  case  is  another 
matter.  The  idea  has  given  rise  to  a  great  deal 
of  ingenuity,  especially  on  the  part  of  Sir  Oliver 
Lodge  and  his  coadjutor  Dr.  Muirhead,  and  it 
may  be  that  their  efforts  will  in  time  be  crowned 
with  complete  success.  In  the  pamphlet  recently 
published,  describing  their  system  of  wireless 
telegraphy,  reference  is  made  to  the  adjustable 
nature  of  the  inductance  coil  and  the  condenser 
as  being  a  means  of  tuning  the  radiator  to  any 
desired  frequency  or  pitch,  and  thus  rendering 
syntony  possible  in  the  receiver.  This  adjust- 
ability, it  is  contended,  makes  it  feasible  so  to 
attune  the  two  circuits  that  they  shall  be  secure 
from  certain  kinds  of  outside  interference.  It 
is  admitted  that  "  for  very  close  tuning  of  this 


A  UNIVERSAL  SYSTEM.  167 

kind  more  elaborate  devices  are  necessary,"  and 
in  Mr.  Marillier's  description  of  their  method  in 
Page's  Magazine  it  is  claimed  that  "  with  the 
close  screening  devices "  which  the  inventors 
have  introduced  into  their  system,  all  "outside 
interference  from  other  stations  outside  a  ten- 
mile  radius  "  can  be  satisfactorily  eliminated. 

The  matter,  however,  is  one  of  detail,  of  which 
perhaps,  more  has  been  made  than  it  deserves ; 
because  whenever  secrecy  becomes  a  thing  of 
vital  importance  codification  is  always  possible. 
Many  hold — Sir  William  Preece,  I  believe, 
among  the  number — that  etheric  wave  telegraphy 
is  by  its  nature  a  universal  system,  and  will  con- 
tinue to  be  such  in  spite  of  efforts  to  the  con- 
trary. The  electromagnetic  waves  travel  in 
every  direction  through  the  ether  from  the  point 
of  excitation,  like  radiations  from  the  center  of 
a  sphere,  and  are  only  stopped  or  turned  from 
their  course  by  matter  of  different  degrees  of  in- 
conductivity.  But  for  this  the  oscillations  would 
radiate  through  the  earth  in  the  same  way  that 
they  radiate  through  the  air.  It  is  supposed, 
however,  that  when  the  electromagnetic  waves 
impinge  upon  the  earth  they  are  stopped  or  de- 
flected. But  it  must  be  confessed  that  our 
knowledge  in  the  matter  is  very  imperfect. 

This  discussion  on  syntony,  however,  has  car- 
ried us  a  little  too  far  ahead,  and  it  is  necessary 
to  go  back  a  little  and  record  the  surprise  with 


1 68     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

which  the  announcement  was  made  on  Decem- 
ber 12,  1901,  that  Marconi  had  at  St.  John's, 
Newfoundland,  received  signals  from  Poldhu, 
Cornwall,  a  distance  of  1,800  miles  across  the 
Atlantic.  These  "  signals "  were  explained  to 
be  nothing  more  than  a  letter  of  the  alphabet 
several  times  repeated,  and  the  public  were  in- 
credulous. The  feat  was  believed  to  be  impos- 
sible ;  but  the  following  month  brought  most 
surprising  confirmation  of  the  wonder.  The 
American  liner  Philadelphia,  fitted  with  the  Mar- 
coni apparatus,  and  with  Marconi  himself  on 
board,  on  her  way  to  New  York,  received  legible 
messages  from  the  Poldhu  station  up  to  a  dis- 
tance of  1,5  5  ii  miles,  and  weak  signals  up  to 
2,099  miles. 

These  experiments  brought  out  one  very  re- 
markable phenomenon ;  for  while,  by  night 
transmission  was  possible  to  upward  of  1,500 
miles,  during  the  daytime  the  utmost  limit  of 
legibility  was  700  miles.  This  difference  Mar- 
coni attributed  to  the  discharging  influence  of 
the  sunlight  upon  the  electricity-laden  vertical 
wire  of  the  transmitter. 

Further  investigations  into  this  phenomenon 
were  made  during  the  voyage  of  the  King  of 
Italy  to  St.  Petersburg  in  July,  1902,  in  the  Carlo 
Alberta.  The  vessel  was  fitted  up  with  wire- 
less telegraphy  apparatus,  and  under  Marconi's 
direction,  signals  and  messages  were  received 


FURTHER  INVESTIGATION.  169 

daily  from  Poldhu.  The  noteworthy  thing 
about  these  experiments  was  not  merely  the 
greatness  of  the  distance  to  which  messages 
were  transmitted,  but  the  circumstance  that  so 
much  of  that  distance  was  overland.  A  detailed 
report  on  these  investigations  was  made  by  Lieu- 
tenant Solari,  of  the  Italian  Navy,  and  from  it, 
as  given  by  Righi  and  Dessau  in  their  work  Die 
Telegraphic  ohne  Draht,  I  take  the  following 
particulars : 

The  receiving  station  on  board  the  Carlo 
Alberta  comprised  two  Marconi  coherers,  which 
carried  the  signals  coming  from  Poldhu  by 
means  of  a  relay  to  an  ordinary  telegraph  ap- 
paratus, which  repeated  them  in  the  Morse 
alphabet,  and  three  of  Marconi's  new  magnetic 
wave  detectors,  which  were  connected  with  a 
telephone.  The  waves  acted  upon  the  coherers 
by  means  of  a  transformer,  which  was  tuned  to 
the  period  of  the  oscillations  radiated  from  the 
sending  apparatus  at  Poldhu.  These  were  re- 
ceived at  first  by  an  arrangement  of  four  isolated 
parallel  wires,  which  were  stretched  from  the 
peak  of  the  foremast  (forty-five  meters  in 
height)  to  the  peak  of  the  mizzen-mast,  and 
thence  down  to  the  receiving  apparatus.  The 
attachments  of  the  wires  were  carefully  insu- 
lated by  chains  of  porcelain  insulators,  and  the 
mast  wire  was  perfectly  insulated  by  means  of 
an  ebonite  tube. 


1 70     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

Later,  however,  while  the  Carlo  Alberta  lay 
off  Cronstadt,  this  arrangement  was  replaced  by 
a  combination  of  fifty  thin  tinned  copper  wires, 
supported  between  the  two  masts  by  a  steel  rope 
(Fig.  42).  This  fan-like  contrivance  was  set  up 
in  order  to  bring  the  oscillatory  period  of  the 
receiver  more  closely  in  unison  with  that  of  the 
sender.  It  should  be  added  that  the  height  of 
the  masts  was,  during  the  return  voyage,  in- 
creased to  fifty-two  meters. 

Messages  were,  as  a  rule,  sent  from  the  Poldhu 
station,  erected  for  transatlantic  communication, 
which  differs  from  the  other  stations  of  the  Wire- 
less Telegraphy  &  Signal  Company  in  possess- 
ing more  powerful  engines  for  generating  the 
electric  waves  and  for  the  effective  directions  of 
the  same.  For  this  latter  purpose  the  station  is 
furnished  with  four  sections  of  100  thin  bare 
conductors  of  tinned  copper,  which  are  sus- 
pended from  four  steel  ropes  stretched  between 
four  open-work  wooden  towers  seventy  meters 
in  height  and  sixty  meters  distant  the  one  from 
the  other.  Above  the  wires  are  about  fifty  centi- 
meters apart,  while  the  lower  ends  are  so  bound 
together  on  the  roof  of  the  station  buildings  that 
the  whole  resembles  a  four-sided  pyramid  with 
its  apex  reversed. 

The  potential  to  which  these  conductors  were 
charged  during  transmission  was  sufficient  to 
cause  sparks  thirty  centimeters  long  to  leap  be- 


AT  THE  POLDHU  STATION.  171 

tween  one  of  the  conductors  and  a  copper  wire 
connected  to  earth. 

It  was  arranged  that  each  midday  between 
the  hours  of  twelve  and  one  and  every  night  be- 
tween the  hours  of  one  and  three,  the  first  ten 


FIG.  42. 

minutes  of  each  quarter  of  an  hour  should  be 
occupied  at  the  Poldhu  station  in  sending  the 
initial  letters  of  Carlo  Alberta  and  the  letter  S, 
and  that  afterward  the  most  interesting  items 
of  the  day's  news  should  be  telegraphed.  The 
experiments  began  under  Marconi's  direction  at 
midday  on  July  7,  at  which  time  the  Carlo 
Alberta  was  near  Dover,  500  nautical  miles  from 
Poldhu,  going  in  a  northeasterly  direction.  Sig- 
nals which  were  received  on  a  magnetic  detector 
were,  in  consequence  of  the  imperfect  syntony 
and  the  disturbing  influence  of  the  sunlight,  not 
very  strong,  although  they  were,  notwithstand- 
ing, clearly  distinguishable.  Telegrams  were  also 


172     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

received  from  the  Cornwall  station  by  means  of 
the  coherer  and  the  Morse  alphabet. 

During  the  ensuing  night  the  Carlo  Alberta 
was  900  kilometers  from  Poldhu ;  nevertheless, 
the  magnetic  detector  distinctly  repeated  the 
signals  from  the  Cornish  station,  while  the 
Morse  apparatus  worked  without  interruption. 
Transmission  was  better  than  during  the  day, 
because  of  the  absence  of  the  disturbing  influence 
of  the  sunlight.  The  following  midday,  when  the 
battle-ship  was  1,000  kilometers  from  Poldhu, 
the  disturbing  influence  of  the  light  was  again 
experienced,  and  it  was  only  on  the  telephone, 
which  was  connected  with  the  detector,  that  the 
signals  of  a  few  S's  were  appreciable.  During 
the  night  of  July  8  and  9,  however,  although 
the  distance  had  considerably  increased  and  the 
whole  breadth  of  England,  as  well  as  the  north- 
ern portion  of  Denmark,  lay  between  the  vessel 
and  the  sending  station,  the  signals  again  arrived 
in  sufficient  strength  not  only  to  act  upon  the 
telephone,  but  to  set  the  Morse  alphabet  in 
activity. 

Before  Cronstadt  the  signals  were  at  first 
difficult  to  make  out  even  during  the  night. 
This  circumstance  was  attributed  to  the  fact 
that  the  water,  with  its  smaller  admixture  of 
salt,  formed  a  poor  conductor  to  earth  in  com- 
parison with  the  salt  water  of  the  ocean.  How- 
ever, the  alteration  in  the  arrangement  of  vertical 


BEFORE  CRONSTADT.  173 

wires,  already  described,  had  the  effect  of  restor- 
ing the  signals  to  their  former  distinctness. 

On  the  return  voyage  from  Cronstadt,  during 
the  night  of  July  22  and  23,  the  Carlo  Alberta 
being  at  the  time  to  the  northeast  of  the  island  of 
Gothland,  the  signals  in  the  telephone  were  so 
distinct  that,  as  the  report  says,  those  who  heard 
them  could  scarcely  believe  that  8,000  kilometers 
of  land  and  water  separated  them  from  the  send- 
ing station.  Later,  through  atmospheric  disturb- 
ances, transmission  became  difficult,  and  about 
2.30  the  signals  altogether  ceased,  although  at 
2.45  the  closing  signal  again  became  quite 
distinct. 

From  July  24,  when  the  Carlo  Alberta  lay  in 
the  inner  harbor  of  Kiel,  till  England  was  again 
reached,  the  signals  from  Poldhu  arrived  with 
such  regularity  and  so  clearly  that  the  magnetic 
detector  and  the  telephone  were  dispensed  with, 
and  the  messages  constantly  received  by  means 
of  a  coherer  and  the  Morse  apparatus.  Equally 
remarkable  results  were  obtained  during  the 
homeward  run  from  England  to  Italy,  but  it  must 
suffice  to  give  one  striking  fact  out  of  many. 
When  the  Carlo  Alberta  was  lying  in  the  harbor 
of  Cagliari,  over  1,580  kilometers  from  Poldhu, 
signals  from  the  latter  place  were  received,  while 
at  a  little  smaller  distance  complete  messages 
were  registered. 

Lieutenant  Solari  sums  up  the  results  of  the 


174    THE  STORY  OF  WIRELESS  TELEGRAPHY. 

experiments  on  board  the  Carlo  Alberta  as  hav- 
ing established  the  following  points:  (i)  that 
there  is  practically  no  limit  to  the  distance  to 
which  the  electric  waves  can  be  sent  if  the  expen- 
diture of  energy  be  proportioned  to  the  distance 
to  be  spanned  5(2)  that  stretches  of  land  between 
the  sending  and  receiving  stations  are  no  hin- 
drance to  transmission;  (3)  that  sunlight  has 
the  effect  of  diminishing  the  carrying  power  of 
the  waves  and  that  therefore  while  it  lasts  a 
greater  expenditure  of  force  is  necessary ;  (4) 
that  as  during  electrical  disturbances  in  the  at- 
mosphere, it  is  essential  that  less  sensitive  receiv- 
ing instruments  should  be  used,  a  greater  amount 
of  electrical  energy  must  be  expended,  and  (5) 
that  the  magnetic  detector,  as  regards  sensitive- 
ness and  reliability,  is  superior  to  every  form  of 
coherer. 

As  regards  the  last  item  it  may  be  that  the 
detector  is  all  that  Solari  says  it  is ;  but  on  that 
point  we  shall  know  more  when  it  has  stood  the 
test  of  longer  experience.  It  is  believed  by  many, 
however,  that  Marconi  possesses  some  special 
secret  which  enables  him  to  do  so  much  more  by 
means  of  his  system  than  others  can  do  with 
theirs,  and  it  may  be  that  it  lies,  in  part,  at  least, 
if  not  wholly,  in  this  detector,  of  which  it  has 
been  said  in  the  Monthly  Review,  by  Mr.  Worth- 
ington,  that  it  raises  Marconi  "  to  the  foremost 
rank  of  scientific  inventors,"  and  removes  from 


THE  MAGNETIC  DETECTOR.  175 

wireless  telegraphy  a  stumbling-block  in  the  way 
of  speed. 

Much  discussion  has  arisen  over  this  "  mag- 
netic detector,"  which  is  nothing  more  than  the 
"  mercury  coherer "  previously  referred  to  in 
speaking  of  Lodge  &  Muirhead's  improved  re- 
ceiver. Mr.  Marconi,  before  the  Royal  Society, 
mistakenly  attributed  the  invention  to  Lieutenant 
Solari.  The  editor  of  the  journal  L'Elettricita, 
published  at  Rome,  intending  to  correct  the 
error,  committed  a  fresh  one  by  quoting  Senor 
Castelli  as  the  inventor  of  the  new  method.  It 
appears,  however,  that  neither  of  these  gentle- 
men have  any  claim  to  be  the  originator  of  the 
mercury  coherer,  the  merit  of  the  invention  really 
belonging  to  Professor  Thomas  Tommasina,  of 
Geneva,  who  brought  it  before  the  notice  of 
the  Physical  Society  of  that  city  in  1899,  and 
published  an  account  of  it  in  the  Comptes  Rendus 
de  1' Academic  des  Sciences  for  May  i  of  that 
year. 

Some  rather  sharp  criticisms  were  passed  on 
Lieutenant  Solari's  performance  by  Mr.  Nevil 
Maskelyne,  superintendent  of  the  wireless  tele- 
graph station  at  Porthcurno,  erected  by  the  East- 
ern Telegraph  Company  for  the  purpose  of  sig- 
naling to  vessels  fitted  with  wireless  installations. 
These  strictures  were  not  so  much  upon  what 
Lieutenant  Solari  put  in  his  report  as  upon  what 
he  left  out.  The  imputation  appears  to  be  that 


176     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

the  naval  officer  was  not  let  into  all  that  was 
going  on  in  connection  with  the  experiments  be- 
tween Poldhu  and  the  Carlo  Alberta,  and  hence 
that  his  account  was  not  a  full  and  complete  one. 
The  gravamen  of  the  charge  is  that,  despite  the 
allegations  of  the  Marconi  Signal  &  Telegraph 
Company  that  they  could  prevent  their  messages 
from  being  "  tapped,"  pretty  nearly  all  that  was 
sent  from  Poldhu  to  the  Carlo  Alberta  en  voyage 
was  intercepted  and  read  by  the  staff  at  the  Porth- 
curno  station,  18  miles  distant ;  and  this  was  done 
even  when  the  attempt  was  apparently  being 
made  to  prevent  such  interception  by  sending  two 
messages,  or  sets  of  signals,  at  the  same  time. 
Mr.  Maskelyne  interprets  the  fact  as  "  an  attempt 
to  prevent  stations  nearer  than  the  Carlo  Alberta 
from  reading  the  message  transmitted  by 
Poldhu,"  and  he  asks  what  had  become  of  the 
Marconi  syntonic  apparatus?  Many  have  been 
asking  since  what  has  become  of  it. 

But,  as  already  said,  this  question  of  syntony 
is  a  detail  which  will  settle  itself  one  way  or 
another  in  course  of  time.  Meanwhile  there  are 
other  matters  of  moment  calling  for  record,  one 
of  which  is  that  the  King  of  Italy  was  so  grati- 
fied by  the  "  wireless  "  experiments  conducted  on 
board  the  Carlo  Alberta  during  the  voyage  to 
St.  Petersburg  and  back  that  he  placed  that  ves- 
sel at  the  disposal  of  Marconi  for  his  projected 
run  to  America  to  test  the  long-distance  stations 


THE  CARLO  ALBERTA. 


177 


of  his  company  at  Cape  Breton,  Canada,  and 
Cape  Cod,  Massachusetts.  The  stations  at  those 
places  are  similar  to  the  one  erected  at  Poldhu, 
of  which  we  have  given  a  description  above.  Of 


FIG.  43.    (From  Tfie  Electrician.) 

the  one  at  Glace  Bay,  Cape  Breton,  we  are  en- 
abled to  give  a  view  in  Fig.  43. 

It  is  needless  to  give  a  detailed  account  of  the 
events  that  led  up  to  the  achievement  of  wireless 
telegraphy  across  the  Atlantic.  Suffice  it  to  say 
than  on  December  22,  1902,  the  famous  Italian 
inventor  was  enabled  to  telegraph,  "  through 
free  space,"  to  King  Edward,  as  follows: 

"To  Lord  Knollys,  Buckingham  Palace,  London. 
"On  occasion  of  first  wireless  telegraphic  communica- 
12 


178     THE   STORY   OF   WIRELESS   TELEGRAPHY. 

tion  across  Atlantic  Ocean  may  I  be  permitted  to  present 
by  means  of  this  wireless  message  transmitted  from  Canada 
to  England  my  respectful  homage  to  his  Majesty  the  King? 

"MARCONI." 

At  the  same  time  the  following  telegram  was 
sent  to  the  King  by  Lord  Minto: 

"To  His  Majesty  the  King,  London. 
"May  I  be  permitted  by  means  of  this  wireless  message 
to  congratulate  your  Majesty  on  success  of  Marconi's  great 
invention  connecting  England  and  Canada  ?      MINTO." 

The  King's  reply  to  Marconi  was  as  follows 
(although  it  is  understood  that  it  was  not  trans- 
mitted to  Canada  by  the  wireless  method)  : 

"To  Marconi,  Canada. 

"I  have  had  the  honor  of  submitting  your  telegram  to  the 
Kmg,  and  I  am  commanded  to  congratulate  you  sincerely 
from  his  Majesty  on  the  successful  issue  of  your  endeavors 
to  develop  your  most  important  invention.  The  King  has 
been  much  interested  by  your  experiments,  as  he  remembers 
that  the  initial  ones  were  commenced  by  you  from  the  royal 
yacht  Osbome  in  1898.  KNOLLYS." 

A  wireless  message  was  also  sent  to  the  King 
of  Italy,  who  replied  as  follows: 

"I  have  learned  with  great  pleasure  of  the  results  you 
have  obtained,  which  constitute  a  triumph  for  yourself,  to 
the  greater  glory  of  Italy  and  of  science." 

The  next  important  step  in  the  history  of  the 
new  telegraphy  was  taken  on  Monday,  March 


THE  LONDON  TIMES.  179 

30,  1903,  when  the  Times  announced  that  it  had 
entered  into  an  arrangement  with  the  Marconi 
Telegraph  Company  for  the  regular  transmission 
of  news  from  the  other  side  of  the  Atlantic. 
This  announcement  was  accompanied  by  the 
publication  of  about  twenty  lines  of  news  from 
the  leading  journal's  New  York  correspondent, 
by  "  Marconigraph,"  partly  on  Saturday  and 
partly  on  Sunday.  An  article  in  the  same  issue 
stated  that  a  day-to-day  transmission  of  news 
between  the  New  and  the  Old  World  had 
been  undertaken  on  a  contract  basis.  After  that 
first  specimen,  however,  no  other  "  Marconi- 
grams  "  appeared,  and  the  director  of  the  com- 
pany had  to  explain  that  the  interruption  of  the 
service  was  due  to  a  breakdown  of  the  apparatus 
at  Cape  Breton.  This  he  felt  confident  would 
be  repaired  very  shortly. 


CHAPTER   XII 

The  system  of  Professor  Braun — The  Orling-Armstrong 
method — Further  particulars  of  the  Lodge-Muirhead 
system — Two  American  wireless  methods — That  of 
Dr.  Lee  de  Forest,  Professor  Fessenden's  Discoveries 
— His  system — The  future  of  wireless  telegraphy. 

HAVING  given  as  complete  an  account  of  the 
Marconi  system  of  wireless  telegraphy,  and  of 
the  marvelous  results  which  it  has  achieved  up 
to  the  present  time,  as  is  possible,  it  remains  to 
refer  with  some  detail  to  several  rival  methods 
that  are  competing  for  public  recognition.  One 
of  the  most  important  of  these  is  that  of  Pro- 
fessor Ferdinand  Braun,  of  Strasburg. 

Professor  Braun  early  came  to  the  conclusion 
that  the  Hertzian  waves  penetrate  the  earth  and 
water  and  spread  out  therein  on  every  side,  just 
as  they  do  in  the  air,  and  that  it  was  possible  to 
turn  them  to  account  for  the  transmission  of 
signals  through  earth  and  water.  But  his  hopes 
of  success  in  this  regard  were  based  upon  the 
fact  that,  while  slow  currents  of  electricity  pene- 
trate and  fill  the  whole  diameter  of  a  conductor, 
like  a  wire,  rapidly  alternating  currents,  or 
Hertzian  waves,  which  we  know,  are  of  great 
velocity,  only  skim,  as  it  were,  along  the  surface, 
1 80 


1 82     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

or,  at  any  rate,  enter  into  the  substance  of  the 
conductor  to  an  extremely  slight  extent.  More- 
over, this  penetration  is  the  less  the  more  quickly 
the  alternations  of  current  follow  one  after 
another. 

Putting  this  law  to  the  test  in  water,  Professor 
Braun  found  that  there  are  no  electric  waves  of 


any  noteworthy  intensity  at  a  depth  of  under 
two  meters  from  the  point  at  which  they  enter. 
He  accordingly  devised  a  series  of  experiments 
to  see  what  results  he  could  obtain  from  the 
action  of  electric  waves  in  the  water.  His  first 
experiments  were  made  in  the  disused  moats  of 
the  old  fortifications  of  Strasburg.  One  of  these 
moats  had  the  form  shown  in  Fig.  44.  The 
transmitting  station  was  placed  at  one  end  of 
the  moat,  at  the  point  marked  a  b,  close  to  a 


PROFESSOR   BRAUN.  183 

quadrangular  space  covered  with  buildings,  by 
reason  of  which  Braun  held  that  direct  trans- 
mission by  electric  waves  through  the  air  was 
next  to  impossible.  The  receiving  station — with 
its  two  wires  dipping  in  the  water — was  removed 
farther  and  farther  from  the  sending  station, 
transmission  remaining  perfectly  distinct  so  long 
as  the  experiments  were  confined  to  the  main 
sheet  of  water.  But  immediately  the  receiving 
wires  were  transferred  to  the  basin  E,  which  was 


FIG.  45. 


FIG.  46. 


connected  with  the  larger  body  of  water  by  a 
shallow  channel  hardly  a  meter  in  breadth,  the 
intensity  of  the  signals  dropped  off  considerably, 
and  was  only  restored  by  a  corresponding 
strengthening  of  the  induction  coil. 

In  these  experiments  Professor  Braun  made 
use  of  variously  contrived  wave-generators,  of 
which  Fig.  45  is  the  simplest  form.  By  spark- 
ing between  the  spheres,  oscillations  are  excited 
which  are  transferred  to  the  surface  of  the  water, 
whence,  according  to  Professor  Braun,  they  pass 


1 84    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

in  part  into  the  water  and  in  part  are  reflected. 
Another  form  of  exciter  is  depicted  in  Fig.  46. 
This  was  found  very  effective.  The  condensers, 
C1  C2,  consisted  of  two  Ley  den  jars  of  about 
2,000  centimeters  capacity,  the  self-induction 
coil  of  spirals  of  from  ten  to  a  hundred  and 
more  turns  of  copper  wire,  the  diameter  of  the 
coils  being  from  three  to  fifteen  centimeters. 
The  right  selection  of  these  coils  was  found  to  be 
very  essential  to  favorable  working. 

Braun  was  satisfied  that  in  these  experiments 
the  results  obtained  were :  ( I )  not  the  effect  of 
waves  through  the  air,  and  (2)  that  they  were 
not  produced  by  induction  in  the  sense  of  Preece's 
experiments. 

Other  experiments  were  subsequently  con- 
ducted on  the  Rhine,  and  with  equally  favorable 
results.  In  the  summer  of  the  following  year 
(1899)  Professor  Braun  tested  his  method  in 
the  sea  at  Cuxhaven,  when,  with  a  Bunsen  bat- 
tery of  eight  cells  and  a  medium-sized  induction 
coil,  and  under  conditions  generally  unfavorable, 
transmission  to  a  distance  of  three  kilometers 
was  completely  successful. 

Notwithstanding  this  success,  however,  Pro- 
fessor Braun  appears  to  have  pursued  these 
investigations  no  further,  but  directed  his  efforts 
in  the  remainder  of  this  and  a  considerable  por- 
tion of  the  ensuing  year  to  experiments  with 
aerial  telegraphy.  In  these  researches,  as  in  those 


HELIGOLAND.  185 

through  the  water,  he  made  the  sender  or  exciter, 
not  the  receiver,  as  with  others,  his  chief  con- 
sideration. During  the  summer  of  1899  atten- 
tion was  chiefly  given  to  testing  the  distance 
for  which  messages  could  be  sent  from  incoming 
or  outgoing  vessels  to  the  lighthouse  Kugelbake 
(Fig.  47),  at  the  mouth  of  the  Elbe,  not  far  from 
Cuxhaven.  The  result  reached  was  that,  with 
the  apparatus  used,  perfect  messages  could  be 
transmitted  to  a  distance  of  thirty-two  kilo- 
meters, while  legible  signals  could  be  sent  to  a 
distance  of  fifty  kilometers. 

The  experiments  were  continued  during  the 
winter  of  1899-1900,  and  through  the  following 
summer,  when  wireless  connection  was  success- 
fully made  with  Heligoland,  a  distance  of  sixty- 
three  kilometers. 

In  the  methods  previously  described  the  chief 
aim  of  the  investigators  has  been  to  turn  water 
and  the  air  to  account  as  media  for  the  trans- 
mission of  electrical  impulses.  But  in  the 
method  which  it  is  now  necessary  to  give,  some 
account  of  transmission  is  effected  through  the 
earth  itself.  It  is  given  out  as  the  joint  invention 
of  Mr.  Axel  Orling,  a  Swedish  electrician,  and 
Mr.  J.  T.  Armstrong,  a  London  engineer,  and 
according  to  one  account,  a  patent  was  taken  out 
for  it  before  that  of  Marconi.  As  a  matter  of 
fact,  however,  the  Orling-Armstrong  method  is 
based  upon  a  number  of  patents,  and  it  may  be 


1 86    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

that  one  or  another  of  them  are  of  earlier  date 
than  that  of  Marconi,  but  all  the  same  the  fact 
remains  that  it  was  not  made  public  until  1902. 
In  any  case,  this  like  all  other  methods,  has  to 
be  judged  by  results,  and  these,  so  far  as  we 
know,  have  not  yet  gone  beyond  the  experimental 
stage. 

The  Orling-Armstrong  invention  differs  from 
other  wireless  systems  in  that,  as  already  said, 
the  earth  is  utilized  as  the  conductor,  and  the  cur- 
rents discharged  are  of  a  very  low  potential,  a 
current  of  eight  volts  being  more  than  sufficient 
to  transmit  a  message  twenty  miles.  It  differs 
from  its  rivals  also  in  its  simplicity,  the 
"  Armorl "  system,  as  its  inventors  call  it,  dis- 
pensing with  induction  coils,  coherers,  high 
masts,  and  the  like,  of  which  we  hear  so  much 
in  connection  with  other  methods. 

The  leading  feature  of  the  invention  consists 
of  an  apparatus  which,  after  the  manner  of  a 
telegraph  relay,  is  designed  to  close  the  circuit 
of  a  telegraphic  receiver  or  some  other  arrange- 
ment operated  by  a  stronger  current.  This 
apparatus  must,  in  accordance  with  its  character, 
answer  to  a  very  weak  current.  It  is  based  on 
the  observation  that,  in  a  sufficiently  narrow, 
funnel-shaped  tube,  of  which  one  part  is  filled 
with  mercury  and  the  rest  with  sulphuric  acid, 
by  the  passage  of  an  electric  current  from  the 
mercury  to  the  acid,  or  vice  versa,  the  two  fluids 


1 88    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

are  caused  to  move  in  the  direction  of  the  current. 
This  phenomena,  which  has  its  origin  in  an 
alteration  in  the  capillary  attraction  of  the  mer- 
cury, has  long  been  known  and  has  been  turned 


FIG. 


to  account  in  the  construction  of  an  extremely 
delicate  electrometer. 

The  simplest  form  of  the  Orling-Armstrong 
apparatus  consists  in  the  main  of  a  siphon  F 
(Fig.  48),  whose  shorter  shank  dips  into  the 
mercury  contained  in  the  chamber  A,  while  the 


THE   ORLING-ARMSTRONG   APPARATUS.    189 

longer  shank,  which  ends  in  the  chamber  B, 
below  the  acid,  is  constricted  to  a  fine  point. 
By  this  means  the  siphon  is  kept  in  a  state  of 
inactivity  and  the  mercury  prevented  from  flow- 
ing from  the  chamber  A  to  the  chamber  B.  If, 
however,  between  the  two  contacts  I  and  J,  of 
which  one  leads  to  the  mercury  in  the  siphon, 
the  other  to  the  acid  in  the  chamber  B,  a  potential 


FIG.  49. 

difference  is  caused  in  the  direction,  so  that  I 
receives  a  positive  charge,  then  the  mercury, 
which  before  had  reached  to  the  summit  of  the 
siphon,  makes  its  way  out  of  the  same  and  falls 
in  minute  drops  on  to  the  lever  K.  This  is  set 
in  motion  thereby  and  establishes  a  contact  at  O, 
which  closes  the  circuit  of  a  battery  and  a  tele- 
graph receiver.  The  reservoir  R  keeps  the  mer- 
cury in  A  at  a  uniform  height. 


1 90    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

A  modification  of  the  arrangement  before  de- 
scribed is  shown  in  Fig.  49,  according  to  which 
the  chamber  B  is  provided  with  a  funnel-shaped 
bottom  V,  having  a  perforation  W  of  such  dimen- 
sions as  will  only  allow  fluid  to  pass  when  under 
pressure.  In  practice  the  chamber  B  is  first  sup- 
plied with  mercury  until  the  pressure  due  to  the 
weight  causes  it  to  begin  to  drip  through.  The 
chamber  is  then  supplied  with  dilute  acid  as 
previously  described.  When,  however,  more 
mercury  is  delivered  by  the  siphon  from  the 
chamber  C,  the  excess  of  pressure  causes  an  equal 
quantity  of  the  mercury  that  was  already  at  the 
bottom  of  the  chamber  B  to 
fall  through  the  perforation 
W,  whereupon  it  comes  in 
contact  with  a  delicately 
poised  lever  K,  by  means  of 
which  a  relay  circuit  is  closed. 
Or,  according  to  the  further  modification  shown 
in  Fig.  50,  the  drop  of  mercury  during  its  de- 
scent is  caused  to  bridge  a  "  break  "  X,  and  so 
close  the  relay  circuit  P. 

Another  form  of  the  invention  is  shown  in 
Fig.  51,  wherein  a  scale-beam,  Y,  is  delicately 
poised  on  a  knife  edge  in  suitable  standards. 
The  scale-beam  consists  of  a  glass  tube,  which 
rests  in  a  suitable  cradle,  2,  and  is  provided  with 
two  upwardly  inclined  limits,  3.  The  tube  con- 
tains a  small  quantity  of  sulphuric  acid  at  the 


ANOTHER   FORM   OF   APPARATUS.        191 

point  D,  where  the  two  limbs  meet,  while  the 
limbs  themselves  are  filled  with  mercury.  To 
the  ends  of  the  scale-beam  are  secured  conduc- 
tors, 4,  which  maintain  electrical  connection 
between  the  mercury  in  the  limbs,  3,  and  the 
mercury  in  the  cups,  5,  into  which  the  conduc- 


FIG.  51. 

tors  dip.  If  a  potential  difference  is  caused 
between  the  mercury  cups,  the  enclosed  drops  of 
acid  in  the  glass  tube,  Y,  will  be  moved  to  one 
side,  the  balance  of  the  scale-beam  will  be  de- 
stroyed, it  will  incline  to  one  side,  and  the  tongue, 
7,  will  be  brought  in  touch  with  one  of  the  con- 
tacts 8  and  9,  whereby  a  local  circuit  will  be 
closed. 

By   means   of  these   various   devices   the   in- 


192     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

ventors  claim  that  electric  currents  which  the 
most  sensitive  galvanometers  can  not  record,  and 
by  which  the  telephone  receiver  is  unaffected,  are 
detected.  The  apparatus  comprises  a  receiver, 
a  small  battery  of  eight  volts,  packed  in  a  case 
provided  on  the  outside  with  two  contact  screws, 
and  two  pointed  iron  stakes  to  be  driven  into 
the  ground  to  a  depth  of  about  eighteen  inches 
and  about  twelve  feet  apart.  To  each  of  them  a 
wire  is  attached  connecting  the  positive  and 
negative  poles  of  the  instruments.  The  current 
thus  set  up  flows  through  these  wires  into  the 
ground  and  so  finds  its  way  to  the  corresponding 
station,  where  similar  iron  stakes  are  planted  in 
the  ground  to  receive  the  impulses.  Each  sta- 
tion is  provided  with  a  key,  similar  to  that  em- 
ployed for  sending  Morse  signals,  together  with 
a  telephone  receiver.  The  operator  holds  the 
telephone  to  his  ear  with  one  hand  while  he 
transmits  in  the  ordinary  way  with  the  other. 
If  necessary  the  receiver  may  be  connected  to  a 
Morse  tape  printing  machine  and  thus  the  mes- 
sages be  printed  as  received. 

Up  to  the  present  time  the  "  Armorl "  system 
has  not  been  worked  to  a  distance  of  more  than 
twenty  miles.  Beyond  that  distance  the  invent- 
ors are  compelled  to  have  recourse  to  relays,  or 
else  to  avail  themselves  of  aerial  transmission. 
For  this  purpose  they  require  a  special  installa- 
tion, with  high  poles,  etc.,  just  like  Marconi  and 


THE  LODGE-MUIRHEAD   SYSTEM.          193 

others;  but  they  claim  as  an  advantage  over 
their  rivals  the  fact  that  their  poles  are  only  one- 
tenth  the  height  of  those  of  Marconi.  They 
claim  a  further  advantage  in  respect  of  speed  of 
transmission. 

There  can  be  no  doubt  that  Messrs.  Orling 
and  Armstrong  are  the  inventors  of  a  very  in- 
genious system  of  wireless  telegraphy,  although 
its  full  capabilities  have  yet  to  be  tested  by  prac- 
tical experience.  Features  greatly  in  its  favor 
are  its  portability  and  its  cheapness.  The  sys- 
tem lends  itself  to  purposes  other  than  those  of 
telegraphy,  as,  for  instance,  to  the  firing  of 
mines,  the  guidance  of  torpedoes,  etc. ;  but  into 
these  matters  it  is  not  necessary  to  enter  here. 

Reference  has  already  been  made  to  the 
Lodge-Muirhead  wireless  system,  and  to  the 
delicate  contrivance  by  which  the  old-fashioned 
filings-tube  coherer  has  been  replaced.  It  re- 
mains to  give  some  particulars  of  other  leading 
features  of  the  system,  which,  as  the  inventors 
claim,  is  based  on  patents  taken  out  for  the  most 
part  in  1897.  These  provide  for  the  following 
essentials : 

i.  The  combination  in  the  transmitting  and 
receiving  circuits  of  two  capacity  areas  and  an 
inductance  coil  as  a  vital  element  in  a  syntonic 
system  of  wireless  telegraphy.  Between  these 
areas,  which  may  be  regarded  as  the  two  coats 
of  a  Ley  den  jar  spread  out  in  space,  is  placed 
13 


194 


THE  STORY  OF  WIRELESS  TELEGRAPHY. 


the  spark-gap,  and  between  this  and  the  lower, 
or  earth-capacity  area  is  the  adjustable  induc- 
tance coil  (Fig.  52).  Sometimes  an  adjustable 
condenser  is  inserted  between  the  lower  or  earth- 
••*  capacity  area  and 

the  adjustable  in- 
ductance coil.  The 
purpose  of  these  is 
to  prolong  the  elec- 
trical oscillations, 
and  by  means  of 
their  adjustment  to 
tune  the  radiator 
or  exciter  to  any 
desired  frequency 
or  pitch,  and  thus 
render  syntony  pos- 


FIG.  52. 

a,  E  the  two  capacity  areas,  s  spark-gap, 
/,,  an  adjustable  self-inductance  coil 
for  adjustment  of  syntony. 


sible  in  the  receiv- 
er. As  has  already 
been  stated,  Sir 
Oliver  Lodge's 
main  idea,  as  regards  transmission,  has  always 
been  to  obtain  a  succession  of  waves  of  definite 
frequency,  the  cumulative  effect  of  which  would 
be  to  produce  a  perceptible  effect  upon  a  tuned 
receiver,  no  matter  how  feeble  the  waves  might 
be,  on  the  well-known  principle  of  sympathetic 
resonance. 

2.  The  second  point  of  importance  laid  claim 
to  by  the  inventors  is  the  use  of  a  transformer, 


A  FORM  OF   CONDENSER. 


195 


or  ironless  induction  coil,  in  the  receiving  cir- 
cuit (tp,  ts,  Fig.  53).  The  purpose  of  this  de- 
vice is,  briefly  stated,  to  magnify  the  electro- 
magnetic force,  and  to  put  the  coherer  into  a  sec- 
ond circuit,  instead  of  in  direct  series  with  the 
vertical  collecting  wire  and  the  lower  capacity, 
or  earth-plate. 

3.  The  third  distinctive  feature  of  the  Lodge- 
Muirhead  system  is  the  use  of  a  condenser  shunt 
(see  Fig.  53)  in  the 
coherer  circuit,  which 
enables  that  circuit  to 
have  a  definite  time 
period.  This  con- 
denser shunt  elimi- 
nates the  battery  and 
receiving  instrument 
so  far  as  oscillations 
are  concerned,  and  is 
regarded  by  the  pat- 
entees as  an  addition 
of  great  importance. 

The  disk  coherer  is 
placed  directly  in  cir- 
cuit with  a  siphon 
recorder,  without  the 
interposition  of  any 
relay,  and  is  con- 
nected also  with  a  potentiometer  for  the  purpose 
of  regulating  the  P.O.  at  its  terminals  from  0.03 


FIG.  S3. 

E  the  two  capacity  areas,  tp  the  prim- 
ary (adjustable)  circuit  of  the  Lodge 
transformer  (or  jigger),  ts  the  second- 
ary circuit  (adjustable)  of  the  trans- 
former, /.,  an  additional  adjustable 
inductance  coil  to  assist  in  the  accur- 
ate tuning  of  the  coherer  circuit,  c  the 
steel  mercury  coherer,  -A'2  adjustable 
condenser  (N.B. — This  condenser  is 
one  of  the  characteristics  of  Lodge's 
system),  R  siphon  recorder. 


196    THE   STORY   OF   WIRELESS   TELEGRAPHY. 

to  0.5  volt,  according  to  circumstances.  The 
coherer  is  so  sensitive,  when  the  disk  is  rotating 
with  moderate  speed,  that  the  application  of  a 
whole  volt  is  sufficient  to  break  down  the  film 
of  oil  and  establish  coherence. 

The  transmitting  circuit  consists  of  an  elevated 
capacity,  in  the  form  of  a  globe,  a  wire-cage 
arrangement,  or  a  framework  of  wires  (as  offer- 
ing as  little  resistance  as  possible  to  the  wind), 
from  which  is  suspended  the  vertical  wire,  con- 
nected at  its  lower  end  to  one  knot  of  the  spark- 
gap.  The  inductance  coil  and  condenser  (when 
one  is  employed)  are  connected  in  series  with 
the  other  knob,  and  a  lead  is  taken  thence  to  the 
earth-plate  or  to  the  center  of  a  second  capacity 
lying  on  the  ground.  The  system  also  includes 
a  Ruhmkorff  coil  for  generating  the  sparks  and 
a  battery  of  five  cells,  more  or  less,  which  is  re- 
placed for  long-distance  work  by  an  alternator. 

The  signaling  apparatus  consists  either  of  a 
specialized  Morse  key,  worked  by  hand,  or,  what 
is  a  distinctive  feature  of  Dr.  Muirhead's  im- 
provements, an  automatic  signaling  machine 
used  in  conjunction  with  a  perforator  of  special 
pattern.  In  either  case  the  local  signaling  cir- 
cuit contains  a  transmitter  designed  to  open  and 
shut  at  a  definite  rate  the  primary  of  the  induc- 
tive coil.  This  instrument  (shown  in  Fig.  54) 
is  made  up  of  two  telegraphic  sounders  cross- 
connected  in  such  a  way  as  to  act  reciprocally. 


198    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

An  aluminium  arm  fitted  with  a  copper  rod  dip- 
ping into  mercury  is  attached  to  the  armature  of 
the  second  sounder,  and  the  rapid  make-and- 
break  between  the  copper  rod  and  the  mercury 
(about  600  times  per  minute)  serves  to  fix  the 
frequency  of  the  sparks.  The  function  of  this 
apparatus,  or  "  buzzer,"  as  it  is  called,  is,  during 
the  holding  down  of  the  Morse  key,  to  cut  up 
the  long-continued  contact  into  a  rapid  succes- 
sion of  sparks,  without  any  attention  on  the  part 
of  the  operator,  so  that  all  he  has  to  do  is  to 
signal  shorts  and  longs  in  the  usual  telegraphic 
manner.  These  are  translated  by  the  "  buzzer  " 
into  the  requisite  mode  of  disturbance  for  spark- 
signaling,  and  are  transmogrified  by  the  receiver 
into  the  dots  and  dashes  of  the  siphon  script. 

This  application  of  ordinary  telegraphic  sig- 
naling apparatus  is  due  chiefly  to  the  ingenuity 
of  Dr.  Muirhead,  and  how  perfectly  it  works 
may  be  seen  by  a  visit  to  the  inventor's  experi- 
mental range  between  Elmers  End  and  Alder- 
shot,  a  distance  of  thirty-four  miles,  which, 
owing  to  the  insulating  nature  of  the  Kentish 
chalk  formation  is  held  by  the  inventors  to  be 
equivalent  to  several  times  that  distance  over 
sea.  The  system  has  been  tested  also  over  the 
official  range  of  sixty-two  miles  between  Port- 
land and  Portsmouth,  and  with  satisfactory  re- 
sults. 

As  already  stated,  the  inventors  are  satisfied 


THE  RISK  OF  CONFUSION.  199 

that  they  can  eliminate  interference  beyond  a 
radius  of  ten  miles.  Within  that  distance  the 
problem  is  more  difficult.  For  ordinary  sea- 
going work,  and  for  communication  between 
ship  and  shore,  they  hold  that  a  simple  open- 
tuned  system  is  at  present  almost  necessary, 
because  of  the  complication  that  would  arise  if 
every  ship  had  to  tune  both  a  closed  oscillating 
condenser  circuit  and  its  attached  aerial  specially 
for  each  station. 

While  the  number  of  vessels  sending  wireless 
signals  or  messages  at  one  time  is  small  the  risk 
of  confusion  is  not  very  great.  But  what  will 
be  the  condition  of  things  when  the  wireless 
equipment  of  ships  becomes  general,  unless  some 
close  system  of  syntonic  signaling  be  devised,  it 
is  not  difficult  to  foresee.  Sir  Oliver  Lodge  and 
his  coadjutor,  Dr.  Muirhead,  have  for  some  time 
been  pressingly  alive  to  the  imminence  of  this 
contingency,  and  they  have  in  consequence  been 
turning  their  attention  to  the  working  out  of  a 
contrivance  to  meet  the  need,  rather  than  to  the 
covering  of  great  distances  by  their  "  wave" 
system. 

They  will  achieve  a  great  thing  if  they  can 
adapt  their  apparatus  to  this  purpose,  and  so 
make  theirs  the  premier  system  as  regards  safety 
and  effectiveness,  if  only  for  short  distances.  It 
is  some  reward  for  their  tireless  labors  in  this 
direction  that  the  first  installation  of  "  wireless  " 


200    THE  STORY   OF  WIRELESS  TELEGRAPHY. 

telegraphy  adopted  by  one  of  the  cable  com- 
panies, that  on  board  the  two  new  repairing 
ships  of  the  Eastern  Extension  Telegraph  Com- 
pany, should  have  been  allotted  to  the  Lodge- 
Muirhead  "  Wireless "  Telegraphy  Syndicate, 
after  a  careful  consideration  of  the  different  com- 
peting systems  at  present  in  vogue. 

It  remains  to  give  a  brief  description  of  two 
other  systems  of  aerial  telegraphy,  the  inventors 
whereof  are  both  Americans.  The  first  is  that 
of  Dr.  Lee  de  Forest,  of  which  much  has  been 
heard  in  connection  with  the  Russo-Japanese 
war,  the  most  interesting  part  of  whose  inven- 
tion centers  in  the  "  responder,"  the  device  by 
which  he  replaces  the  coherer  of  other  methods. 
This  apparatus,  according  to  the  description  of 
the  company  working  the  system,  depends  for  its 
action  upon  an  electrolytic  principle.  Between 
two  electrodes  of  soft  metal  is  fixed  a  paste  con- 
taining some  electrolizable  fluid,  metallic  par- 
ticles, and  some  viscous  material.  Under  the 
action  of  the  local  battery,  minute  conducting 
particles  are  torn  off  from  the  electrodes  and 
made  to  bridge  the  gap.  The  resistance  of  the 
device  is  therefore  ordinarily  very  small,  but 
under  the  action  of  the  electric  waves  electroly- 
sis is  set  up,  and  minute  hydrogen  bubbles  are 
generated  at  the  cathode.  This  suddenly  dis- 
rupts the  conducting  chains  and  greatly  increases 
the  resistance  of  the  responder.  The  oxygen 


THE   DE   FOREST   METHOD.  2OI 

appears  to  combine  with  the  anodic  metal,  while 
the  hydrogen  amalgamates  with  a  depolarizing 
agent  mixed  with  the  paste.  The  action  is  thus 
instant  and  automatic,  and  allows  the  use  of  a 
telephone  as  receiver.  As  a  proof  of  the  sensi- 
tiveness of  the  responder,  it  is  said  that  it  will 
respond  to  a  -fa  inch  spark  45  feet  away  with 
antennae  only  2  feet  in  height. 

The  receiving  apparatus  includes  also  an  ad- 
justable inductance,  an  adjustable  capacity,  a 
potentiometer,  a  telephone,  and  a  fixed  capacity. 
The  adjustable  inductance  and  the  adjustable 
capacity  serve  for  varying  the  time  constant  of 
the  oscillating  circuit,  in  order  that  the  circuit 
may  be  put  as  nearly  as  possible  in  tune  with 
the  transmitted  waves.  The  object  of  the  poten- 
tiometer is  to  obtain  the  loudest  possible  sound 
in  the  telephone  receiver. 

As  regards  the  sending  apparatus,  an  ordinary 
alternating  current  is  used  in  place  of  interrupt- 
ers or  coils.  A  special  key  is  employed  for 
breaking  the  current,  and  with  it  a  speed  of  up- 
ward of  48  words  per  minute  is  said  to  have 
been  reached. 

One  of  the  more  salient  features  of  the  De 
Forest  method  is  a  "  reactance  regulator,"  the 
true  function  of  which  is  to  prevent  the  forma- 
tion of  an  arc  across  the  spark-gap  in  case  the 
energy  of  delivery  to  the  circuit  becomes  excess- 
ive. Should  a  tendency  to  arc  at  the  gap  arise, 


202     THE   STORY   OF   WIRELESS   TELEGRAPHY. 

the  handle  of  the  reactance  regulator  may  be  so 
worked  as  to  bring  in  more  turns  of  wire  and 
thus  reduce  the  excess  of  energy.  Another  fea- 
ture of  interest  is  a  helix,  consisting  of  four 
turns  of  quarter-inch  nickel-plated  copper  tube, 
and  having  a  diameter  of -about  eighteen  inches. 
By  means  of  a  movable  contact  the  self-induction 
in  the  circuit  is  readily  variable,  while  owing  to 
the  very  high  oscillating  frequency,  the  slightest 
movement  effects  a  difference  in  the  nature  of 
the  waves  thrown  off.  This  helix  forms  a  most 
important  part  of  the  apparatus,  as  by  its  means 
an  approach  to  syntony  is  said  to  be  attained. 

Another  feature  of  the  De  Forest  system  is  the 
five-wire  antennae  attached  to  both  the  transmit- 
ter and  receiver.  In  transmitting  the  whole  of 
the  five  wires  are  in  parallel,  while  in  receiv- 
ing only  four  are  parallel,  though  they  are  in 
series  with  the  remaining  one.  By  this  arrange- 
ment the  spark-gaps  on  the  receiving  side  act  as 
insulators. 

The  De  Forest  method  has  frequently  been 
worked,  and  with  every  satisfaction,  in  connec- 
tion with  the  American  army  and  navy  opera- 
tions ;  while  in  the  month  of  December,  1903, 
Dr.  de  Forest  made  a  series  of  successful  experi- 
ments in  the  transmission  of  aerial  signals  and 
messages  between  Holyhead  and  Howth,  a  dis- 
tance, as  the  crow  flies,  of  65  miles,  when  a 
speed  of  from  20  to  30  words  per  minute  was 


PROFESSOR    FESSENDEN'S   SYSTEM.        203 

obtained.  It  is  worthy  of  note  that  the  inventor 
makes  no  claim  to  having  achieved  perfect 
syntony,  which  he  holds  to  be  impossible  at 
present. 

The  other  system  of  wireless  telegraphy 
whereof,  before  concluding,  it  is  necessary  to 
give  some  account,  is  that  of  Professor  Fessen- 
den, a  brief  reference  to  whom  has  already  been 
made.  Professor  Fessenden  was  until  recently 
connected  with  the  teaching  staff  of  the  Alle- 
ghany  University,  and  it  was  while  there  that  he 
worked  out  his  remarkable  system.  It  is  en- 
titled to  the  distinguishing  adjective  because,  as 
was  observed  in  a  descriptive  article  in  the  Elec- 
trical World  of  New  York,  the  inventor  "  has 
not  only  evolved  apparatus  entirely  different 
from  that  of  his  contemporaneous  workers 
abroad,  but  has  discovered  new  phenomena 
separate  and  distinct  from  those  of  Hertz,  '  in 
that  they  are  not  complete  waves,  but  only  half 
waves,  and  in  that  they  travel  on  the  surface  of 
a  conductor,  and,  hence,  unlike  Hertz  waves,  can 
be  deflected  from  a  straight  line.' "  These 
waves  are  described  as  "  semi-free  ether  waves," 
but  are  "  different  from  those  investigated  by 
Lodge  in  metal  conductors,  in  that  they  are  not 
current  waves." 

Fessenden,  in  one  of  his  patent  specifications,* 
thus  refers  to  these  electromagnetic  waves :  "  In 
*  No.  706,746. 


204    THE   STORY   OF  WIRELESS   TELEGRAPHY 

the  Lodge  waves  the  electric  energy  is  maximum 
when  the  magnetic  energy  is  minimum,  and  all 
energy  not  absorbed  by  resistance  losses  is  re- 
coverable, while  with  the  form  investigated  by 
me  the  electric  energy  is  a  maximum  at  the  same 
time  as  the  magnetic,  and  none  of  the  energy 
radiated  is  recoverable  except  by  deflection.  I 
have  found  that  it  is  essential  for  the  proper 
sending  and  receipt  of  these  waves  that  the  sur- 


FIG.  55. 

face  over  which  they  are  to  travel  should  be 
highly  conducting,  more  especially  in  the  neigh- 
borhood of  the  point  where  the  waves  are  gen- 
erated." 

The  salient  features  of  Professor  Fessenden's 
system  may  be  seen  from  the  accompanying  dia- 
grams (Figs.  55  and  56).  Fig.  55  represents 
what  the  originator  designates  a  "  wave-chute," 


A   NOVEL   FEATURE.  205 

wherein  i  is  the  antenna  or  sending-  conductor, 
and  2.  the  grounded  conductor  leading  across 
buildings  and  other  obstacles  to  a  \/4  or  more, 
beyond  the  limits  of  obstructions,  when  the  ter- 
minals are  earthed,  as  shown.  The  coils  3  and 
4,  forming  guys  from  the  mast,  have  a  natural 
period  of  oscillation,  different  from  that  of  the 
sending  conductor,  and  this,  with  the  grounded 
conductor  or  wave-chute,  eliminates  outside  in- 
terference of  wave-lengths  not  in  tune,  and  dis- 
sipates atmospheric  potentials  which  ordinarily 
produce  untoward  effects  in  the  reception  of 
wireless  messages. 

Another  novel  feature  of  the  antenna  and 
oscillator  system,  says  the  account  to  which  we 
are  chiefly  indebted  for  these  facts,*  "  is  due  to 
the  inventor's  discovery  that,  if  electromagnetic 
waves  were  produced  in  a  medium  having  a 
specific  inductive  capacity  and  permeability  to 
electromagnetic  waves  greater  than  air,  the 
height  of  the  antenna  may  be  considerably  re- 
duced, since  '  the  periodicity  of  oscillation  is  de- 
creased compared  with  that  of  the  same  antenna 
in  air ;  and  the  radiation  is  therefore  increased, 
giving  the  effect  of  a  long  conductor.' "  In 
order  to  accomplish  this  end  the  conductor  with 
the  oscillator  is  placed  within  a  second  conductor 
of  tubular  form,  which  is  immersed  "  in  water 
or  other  liquid  having  an  electric  constant 

*  The  Electrical  World  and  Engineer  of  New  York. 


206    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

greater  than  that  of  air,  and  on  which  the  emit- 
ted wave  length  depends." 

At  his  transmitting  station  Fessenden  uses  a 
vertical  wire  with  large  capacity  and  low  induc- 
tion. The  capacity  can  be  regulated  by  increas- 
ing the  area  of  the  antenna  and  the  induction  by 
adding  to  the  turns  of  wire  connecting  the  ver- 
tical wire  with  the  source  of  energy. 

One  of  the  strongest  points  claimed  for  Fes- 
senden's  apparatus  is  that  by  its  means  messages 
may  be  sent  at  a  much  higher  rate  of  speed  than 
is  possible  by  the  ordinary  method  of  making 
and  breaking  the  primary  circuit.  Another  point 
in  its  favor  is  that  signals  can  be  sent  by  it  to  a 
much  greater  distance  with  a  slighter  expenditure 
of  power  than  by  other  systems.  Still  another 
advantage  claimed  for  it  is  the  accuracy  of  its 
message  delivery,  being  equal,  as  is  said,  in  this 
respect  to  transmission  by  wire. 

In  Fig.  56  the  complete  sending  and  receiving 
apparatus  is  diagrammatically  shown ;  i  being  a 
conductor,  connected  to  one  of  the  terminals  of 
the  induction  coil  2,  the  other  terminal  being 
grounded.  A  switch,  3,  is  arranged  in  the  con- 
trolling circuit  of  the  generator  (induction  coil), 
so  as  to  permit  of  the  generator  being  rendered 
inoperative  when  the  apparatus  is  employed  as 
a  receiver.  When  transmitting,  it  is  preferred 
that  the  generator  should  be  kept  constantly  in 
action.  When  the  generator  is  thus  in  operation 


A   DIAGRAM    OF    THE   APPARATUS.        207 

a  key,  4,  is  employed  to  throw  the  antenna  out 
of  tune  with  the  station  to  which  signals  are 
being  sent.  This  is  effected,  as  already  said, 


FIG.  56. 

not  by  making  and  breaking,  but  by  short  cir- 
cuiting, more  or  less,  the  tuning  device,  which 
is  arranged  in  series  with  the  conductor  I, 
and  preferably  between  the  generator  and  the 

ground. 


208     THE   STORY   OF  WIRELESS   TELEGRAPHY. 

In  the  receiving  circuit  the  conductor,  i,  the 
condenser,  12,  and  a  combined  capacity  and  in- 
ductance forming  a  tuning  gird,  13,  are  con- 
nected in  series ;  but  the  condenser  and  com- 
bined inductance  and  capacity  are  in  shunt  to  the 
spark-gap,  and  hence  in  parallel  with  the  trans- 
mitting conductor. 

For  the  sake  of  speed  Fessenden  uses  the  tele- 
phone receiver,  and  as  this  necessitates  the  em- 
ployment of  some  form  of  detector  more  rapid 
than  the  ordinary  coherer,  the  inventor  has  con- 
trived an  instrument  somewhat  on  the  principle 
of  the  bolometer.  But  in  place  of  having  a 
large  radiating  or  absorbing  surface  in  propor- 
tion to  its  mass,  the  reverse  obtains,  with  the 
result  that  conductor  losses  exceed  those  by 
radiation. 

The  heat  capacity  is  so  small  that  an  infin- 
itesimal amount  of  energy  is  sufficient  to  heat 
it.  These  effects  are  obtained  by  a  short  loop  of 
silver  wire,  having  a  diameter  of  0.002  inches, 
and  having  a  platinum  core  of  0.00006  inches  in 
diameter,  fastened  to  the  leading-in  wires,  which 
are  sealed  in  a  glass  bulb.  The  tip  of  the  loop 
is  immersed  in  nitric  acid  and  the  silver  dis- 
solved so  as  to  expose  the  platinum.  In  order 
further  to  reduce  loss  of  radiation  by  heat  the 
loop  is  enclosed  in  a  silver  shell.  The  sensi- 
tiveness of  the  detector  may  be  heightened  by 
exhausting  the  bulb. 


AN  EARLIER   FORM.  209 

An  earlier  form  of  Fessenden  detector  con- 
sists of  a  silver  ring  resting  on  two  knife  edges 
of  silver,  and  a  third  edge  of  carbon.  This 
forms  a  microphonic  contact,  and  may  be  em- 
ployed as  converter  of  electromagnetic  waves 
into  Morse  signals.  It  is  only  necessary  to  add 
to  this  brief  account  that  the  numbers  32,  33,  and 
34  (Fig.  56)  refer  to  the  call  apparatus,  32  being 
a  coherer,  33  a  transformer,  and  34  a  telephone 
bell  or  other  alarum-like  mechanism.  Another 
coherer,  35,  connects  the  antenna  with  the 
ground — this  to  protect  the  apparatus  from  pos- 
sible injury  by  atmospheric  electricity. 

It  will  be  seen  from  these  brief  details  that 
Professor  Fessenden's  system  is  a  very  novel 
and  original  one.  It  is  claimed,  indeed,  on  its 
behalf*  that  "  it  differs  so  widely  from  the  sys- 
tems previously  used  that  it  may  be  considered  of 
a  different  class,"  and  such  in  truth  it  is.  It 
differs  wholly  from  the  coherer  methods  em- 
ployed by  other  investigators,  although  some  of 
the  contrivances  characteristic  of  Fessenden's 
system  appear  to  have  been  simultaneously  hit 
upon  by  other  experimenters.  One  of  the  most 
recent  additions  to  the  system  is  a  device  called 
by  the  inventor  a  "  barretter."  It  is  thus  named 
because  of  its  property  of  "  exchanging  a  given 
amount  of  single  frequency  energy  for  contin- 
uous-current energy."  A  small  column  of  liquid 

*  The  Electrical  World  and  Engineer  of  New  York. 
14 


210    THE   STORY   OF  WIRELESS   TELEGRAPHY. 

is  employed  in  place  of  the  platinum  wire 
already  described.  It  may  take  the  shape  of  a 
diaphragm  with  a  minute  hole  in  it,  connected 
to  a  body  of  liquid ;  or  a  minute  wire  may  be 
immersed  in  the  liquid  so  as  to  concentrate  its 
resistance  about  the  point.  The  sensitiveness 
of  this  form  is  said  to  be  much  greater  than  that 
of  the  hot-wire  barretter,  as  well  as  greater  than 
that  of  the  mercury  coherer. 

The  use  of  this  "  current-operated  constantly 
receptive  receiver  "  in  place  of  the  voltage-oper- 
ated coherer  is  one  of  the  leading  features  of  the 
Fessenden  system.  It  is  affirmed  that  by  its  use 
alone  can  sharp  tuning  be  accomplished.  In  this 
respect  Professor  Fessenden  claims  to  have  gone 
further  than  any  of  his  competitors  in  wireless 
telegraphy.  His  system,  like  that  of  Dr.  de 
Forest,  has  been  severely  tested  in  the  United 
States  and  has  come  successfully  out  of  its  trials. 
It  is  now  being  worked  by  a  company,  and  bids 
fair  to  have  an  important  future. 

The  same,  indeed,  may  be  said  of  most  of  the 
systems  here  briefly  described.  They  are  scor- 
ing fresh  achievements  daily,  making  wireless 
communication  surer  at  every  step,  and  making 
it  more  and  more  a  necessity  to  the  world's  busi- 
ness and  pleasure.  As  to  the  larger  question  of 
the  meaning  and,  as  we  may  say,  the  origin  of 
the  electromagnetic  waves  which  render  possible 
this  aerial  telegraphy,  that  is  another  story  and 


FRESH   ACHIEVEMENTS.  211 

can  not  be  gone  into  here,  although  like  New- 
ton's law  of  gravitation,  it  opens  up  a  new 
era  in  the  realm  of  cosmic  research  and  dis- 
covery. 


THE   END. 


INDEX 


Adams,  Professor,  55 
Admiralty,  British,  156 
"Armorl"  system,  192  et  seq. 
Armstrong,  see  Orling    &  Arm- 
strong 

Association  Franchise,  158 
Atlantic,  first  message  across,  178 


B 


Balloon  trials,  160 

Bell,  Graham,  16-17,  49)  56i  58> 

65 

Bonelli,  40 

Bose,  Professor,  124,  131 
Bouchot,  -40 
Bourbouze,  44 
Branly's    Radioconductor,     113, 

120,  123 

Braun,  Professor,  180-183 
British  Association,  158 
Brown,  A.  C.,  16-65 


Cables,  improvements  in,  48 
Calzecchi-Onesti,    Signor,     120- 

J34 

Cardew,  Major,  74 
Carlo,  Alberta,  168,  170,  172, 176 
Clerk-Maxwell,  14,  15,  101,  105, 

Coherer,  113,  122,  125,  128,  141 

et  seq. 
Cohesion,  first  time  of,  122 


Conduction,  10,  n 

Cooke  (and  Wheatstone),  26,  30 

Cronstadt,  170 

Crookes,  Sir  William,  108,  in 


D'Almeida,  43 

De  Forest,  Dr.,  200  et  seq. 

Derby,  Lord,  34 

Dering,  George  E.,  32,  45 

Dessau,  Bernhard,  135,  169 

Dolbear,  Professor,  58,  61,  63,65 

Donat,  40 

Dufour,  H.,  49 


Edison,  Thomas  A.,  49,  68,  70 
Electromotograph,  71 
Evershed,  Wm.,  97 


Fahie,  J.  J.,  112 

Faraday,  13 

Fessenden,   Professor,    126,    203 

et  seq. 

Funken-Telegraphie,  155 
Future  of  wireless  telegraphy,  210 


Gauss,  18 
Gilliland,  68 


213 


214     THE 'STORY  OF  WIRELESS  TELEGRAPHY. 


Gower-Bell  telephone,  74 
Granville,  W.  P.,  87 
Guitard,  119 

Marillier,  Mr.,  167 
Maskelyne,  Nevil,  175,  176 
Maxwell,  see  Clerk-Maxwell 
Melhuish,  W.  F.,  45 

H 

Minto,  Lord,  178 

Morse,  S.  F.  B.,  22,  23 

Heaviside,  Mr.,  77 

Muirhead,   Dr.   Alexander,    125, 

Helmholz,  Von,  102 

126,  166,  175,  193,  196 

Henry,  Professor,  54 

Hertz,  15,  16,  17,  58,  101,  102, 

104,   107,  118,  130,  132,  140, 

N 

203 
Highton,  Henry,  40,  45 
Huber,  15 
Hughes,   D.  E.,  Prof.,   108, 

Naval    Maneuvers,  British,   159 
Navy  Board,  U.S.,  experiments, 
161 

112,  114,  II5-II6 

Huxley,  Professor,  115,  116 

Newfoundland,  signals  to,  168 

I 

O 

Induction,  10,  n 
Italy,  King  of,  168,  178 

Onesti,  ese  Calzecchi-Onesti 
Orling  and  Armstrong,  97,  185, 

186 

J 

Jackson,  Captain,  123 

P 

Phelps,  67 

K 

Poldhu,  Marconi  station  at,  166, 

Kelvin,  Lord,  31,  102 
Kiel,  173 
King  Edward,  177 
Knollys,  Lord,  177,  178 

168,  171,  176 
Popoff,  Professor,  127,  128 
Porthcurno,   175 
Preece,  Sir  William  H.,  73,  75,  80, 
93,  96,  99,  115,  132,  135,  147, 

167 

L 

R 

Lindsay,  James  Bowman,  32, 

Lodge,    Sir  Oliver  J.,  57,   in, 

Radioconductor,   Branly's,    113, 

112,  118,  134,  159,  166,  175, 
194 
Loomis,  Mahlon,  46,  47 

I2O,    123 

Radiophony,   16 
Rathenau,  Prof.  Emil,  93,  94,  95, 
96 

Rathenau,  W.,  93 

M 

Resonance,  see  Syntony 

Righi,  Professor,  124,  131,  133, 

Marconi,  58,  63,  101,  124,  128, 

136,  169 

130,  134,  137,  139,  141,  144, 

Rubens,  Dr.,  93 

149,  152,  155,  161,  165,  169 

Rutherford,  Mr.,  123 

INDEX. 


215 


st.14/ 


Sacher,  E.,  49 

Salisbury  Plain,  experiments  on, 


ohn's,  signals  received  at, 


Siemens,  16 

Slaby,  Professor,  153,  154 
Slaby-Arco  method,  126 
Smith,  Willoughby,  16,66,  85,  87 
Solari,  Lieutenant,  169,  173,  174 
Spottiswoode,  Mr.,  116 
Steinheil,  C.  A.,  18,  19,  21,  35,  50 
Stevenson,  Chas.  A.,  89,  90,  91, 

100 

Stokes,  Prof.,  116 
Strechner,  96 
Stroh,  Mr.,   116 


Telegraphic        communication 
with  trains,  65 


Telephone,     invention     of,    49; 

Gower-Bell,    74 
Times  (London),  178 
Tommasina,  Prof.  T.,  175 
Trains,     telegraphic     communi- 
cation with,  65,  68 
Trowbridge,  Professor,  49, 50, 51, 
65,  72 


Vail,  Alfred,  24 
Vallot,  159 
Varley,  S.  A.,  119 


W 

Weber,  18 

Wheatstone  (  &  Cooke),  26,  30 
Wilkins,  J.  W.,  26,30,31 
Wimereux,  station  at,  156 
Worthington,  Mr.,   174 


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Studies  in  Spectrum  Analysis. 

By  J.  NORMAN  LOCKYER,  F.  R.  S.,  Correspondent  of  the 
Institute  of  France,  etc.  With  60  Illustrations.  I2mo. 
Cloth,  $2.50. 

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MODERN  SCIENCE  SERIES. 

Edited  by  Sir  JOHN  LUBBOCK,  Bart.,  F.  R.  S. 

<J~HE   CAUSE    OF  AN  ICE  AGE.    By  Sir  ROBERT 
•*•       BALL,  LL.  D.,   F.  R.  S.,    Royal  Astronomer  of  Ireland; 

Author  of  "  Star  Land,"  "  The  Story  of  the  Sun,"  etc. 
"  Sir  Robert  Ball's  book  is,  as  a  matter  of  course,  admirably  written. 
Though  but  a  small  one,  it  is  a  most  important  contribution  to  geology." — 
London  Saturday  Review, 

<J~HE  HORSE,    A  Study  in  Natural  History.     By  WIL- 
•*•       LIAM  H.  FLOWER,  C.  B.,  Director  in  the  British  Natural 

History  Museum.     With  27  Illustrations. 

"  Something  not  heretofore  written  will  be  found  in  this  book.  The  vol- 
ume gives  a  large  amount  of  information,  both  scientific  and  practical,  on 
the  noble  animal  of  which  it  treats."— New  York  Commercial  Advertiser. 

n~HE  OAK.     A  Study  in   Botany.     By  H.  MARSHALL 

•*       WARD,  F.  R.  S.    With  53  Illustrations. 

"  From  the  acorn  to  the  timber  which  has  figured  so  gloriously  in  Eng- 
lish ships  and  houses,  the  tree  is  fully  described,  and  all  its  living  and  pre- 
served beauties  and  virtues,  in  nature  and  in  construction,  are  recounted 
and  pictured." — Brooklyn  Eagle. 

rjTHNOLOGY   IN  FOLKLORE.       By  GEORGE  L. 
•*-•'    GOMME,  F.  S.  A.,  President  of  the  Folklore  Society,  etc. 

"The  author  puts  forward  no  extravagant  assumptions,  and  the  method 
he  points  out  for  the  comparative  study  of  folklore  seems  to  promise  a  con- 
siderable extension  of  knowledge  as  to  prehistoric  times." — Independent. 

<J~HE  LA  WS  AND  PROPERTIES  OF  MA  TTER. 
*        By  R.  T.  GLAZEBROOK,  F.  R.  S.,   Fellow  of  Trinity  Col- 
lege, Cambridge. 

"  It  is  astonishing  how  interesting  such  a  book  can  be  made  when  the 
author  has  a  perfect  mastery  of  his  subject,  as  Mr.  Glazebrook  has.  One 
knows  nothing  of  the  world  in  which  he  lives  until  he  has  obtained  some 
insight  of  the  properties  of  matter  as  explained  in  this  excellent  work." — 
Chicago  Herald. 

<T~HE  FA  UNA  OF  THE  DEEP  SEA.     By  SYDNEY 
•*       J.  HICKSON,  M.  A.,  Fellow  of  Downing  College,  Cam- 
bridge.   With  23  Illustrations. 

"  This  excellent  book  has  a  score  of  illustrations  and  a  careful  index  to 
add  to  its  value,  and  in  every  way  is  to  be  commended  for  its  interest  and 
its  scientific  merit."— Chicago  Times. 

Each,  lamo,  cloth,  $1.00. 


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D.  APPLETON   AND    COMPANY'S   PUBLICATIONS. 

PIONEERS  OF  SCIENCE  IN  AMERICA,  sketches 

•*  of  their  Lives  and  Scientific  Work.  Edited  and  revised  by 
WILLIAM  JAY  YOUMANS,  M.  D.  With  Portraits.  8vo. 
Cloth,  $4.00. 

Impelled  solely  by  an  enthusiastic  love  of  Nature,  and  neither  asking  nor 
receiving  outside  aid,  these  early  workers  opened  the  way  and  initiated  the 
movement  through  which  American  science  has  reached  its  present  com- 
manding position.  This  book  gives  some  account  of  these  men,  their  early 
struggles,  their  scientific  labors,  and,  whenever  possible,  something  of  their 
personal  characteristics.  This  information,  often  very  difficult  to  obtain, 
has  been  collected  from  a  great  variety  of  sources,  with  the  utmost  care  to 
secure  accuracy.  It  is  presented  in  a  series  of  sketches,  some  fifty  in  all, 
each  with  a  single  exception  accompanied  with  a  well-authenticated  portrait 

"  Fills  a  place  that  needed  filling,  and  is  likely  to  be  widely  read." — 
New  York  Sun. 

"  It  is  certainly  a  useful  and  convenient  volume,  and  readable  too,  if  we 
judge  correctly  of  the  degree  of  accuracy  of  the  whole  by  critical  examina- 
tion of  those  cases  in  which  our  own  knowledge  enables  us  to  form  an  opin- 
ion. ...  In  general,  it  seems  to  us  that  the  handy  volume  is  specially  to  be 
commended  for  setting  in  just  historical  perspective  many  of  the  earlier 
scientists  who  are  neither  very  generally  nor  very  well  known." — New  York 
Evening  Post. 

"  A  wonderfully  interesting  volume.  Many  a  young  man  will  find  it 
fascinating.  The  compilation  of  the  book  is  a  work  well  done,  well  worth 
the  doing."— Philadelphia  Press. 

"  One  of  the  most  valuable  books  which  we  have  received." — Boston 
Advertiser. 

"A  book  of  no  little  educational  value.  .  .  .  An  extremely  valuable  work 
of  reference."— Boston  Beacon. 

"  A  valuable  handbook  for  those  whose  work  runs  on  these  same  lines, 
and  is  likely  to  prove  of  lasting  interest  to  those  for  whom  '  les  documents 
humain  '  are  second  only  to  history  in  importance— nay,  are  a  vital  part  of 
history." — Boston  Transcript. 

"  A  biographical  history  of  science  in  America,  noteworthy  for  its  com- 
pleteness and  scone.  ...  All  of  the  sketches  are  excellently  prepared  and 
unusually  interesting." — Chicago  Record. 

"  One  of  the  most  valuable  contributions  to  American  literature  recently 
made.  .  .  .  The  pleasing  style  in  which  these  sketches  are  written,  the 
plans  taken  to  secure  accuracy,  and  the  information  conveyed,  combine  to 
give  them  great  value  and  interest.  No  better  or  more  inspiring  reading 
could  be  placed  in  the  hands  of  an  intelligent  and  aspiring  young  man." — 
New  York  Christian  Work. 

"A  book  whose  interest  and  value  are  not  for  to-day  or  to-morrow,  but 
for  indefinite  time."— Rochester  Herald. 


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THE  PERENNIAL  CONFLICT. 

The  Warfare  of  Science  with  Theology. 

A  History  of  the  Warfare  of  Science  with  The- 
ology in  Christendom.  By  ANDREW  D.  WHITE, 
LL.  D.  (Yale),  L.  H.  D.  (Col.),  Ph.  D.  (Jena),  late 
President  and  Professor  of  History  at  Cornell  Uni- 
versity. In  two  volumes,  8vo.  Cloth,  $5.00. 

"Able,  scholarly,  critical,  impartial  in  tone  and  exhaustive  in 
treatment." — Boston  Advertiser. 

"  The  most  valuable  contribution  that  has  yet  been  made  to 
the  history  of  the  conflicts  between  the  theologists  and  the  scien- 
tists." — Buffalo  Commercial, 

"  A  work  which  constitutes  in  many  ways  the  most  instructive 
review  that  has  ever  been  written  of  the  evolution  of  human 
knowledge  in  its  conflict  with  dogmatic  belief."— Boston  Beacon. 

"  The  same  liberal  spirit  that  marked  his  public  life  is  seen  in 
the  pages  of  his  book,  giving  it  a  zest  and  interest  that  can  not 
fail  to  secure  for  it  hearty  commendation  and  honest  praise." — 
Philadelphia  Public  Ledger. 

"  Such  an  honest  and  thorough  treatment  of  the  subject  in  all 
its  bearings  that  it  will  carry  weight  and  be  accepted  as  an  author- 
ity in  tracing  the  process  by  which  the  fcientific  method  has  come 
to  be  supreme  in  modern  thought  and  life. " — Boston  Herald. 

"  The  story  of  the  struggle  of  searchers  after  truth  with  the 
organized  forces  of  ignorance,  bigotry,  and  superstition  is  the 
most  inspiring  chapter  in  the  whole  history  of  mankind.  That 
story  has  never  been  better  told  than  by  the  ex-President  of  Cor- 
nell University  in  these  two  volumes." — London  Daily  Chronicle. 

"  It  is  graphic,  lucid,  even-tempered—never  bitter  nor  vindic- 
tive. No  student  of  human  progress  should  fail  to  read  these  vol- 
umes. While  they  have  about  them  the  fascination  of  a  well-told 
tale,  they  are  also  crowded  with  the  facts  of  history  that  have  had 
a  tremendous  bearing  upon  the  development  of  the  race." — 
Brooklyn  Eagle. 


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"A  BUTTERFLY  BOOK  OF  BEAUTY," 

How  to  Know  the  Butterflies. 

By  JOHN  HENRY  COMSTOCK,  Professor  of  Ento- 
mology in  Cornell  University,  and  ANNA  BOTSFORD 
COMSTOCK,  Lecturer  in  Nature  Study  in  Cornell 
University.  With  45  full-page  colored  plates,  and 
many  illustrations  in  the  text.  8vo.  Cloth,  $2.25 
net ;  postage  additional. 

This  book  is  designed  as  a  general  treatise  on  butter- 
flies and  a  manual  of  the  species  of  the  United  States  east 
of  the  Rocky  Mountains.  It  is  intended  especially  for 
beginners  and  for  students  of  nature ;  but  it  will  also 
serve  as  an  introduction  to  a  serious  study  of  this  group 
of  insects.  This  book  is  richly  illustrated,  without  a  con- 
fusing array  of  figures  of  species  from  remote  parts  of  our 
country ;  it  contains  brief  descriptions  of  species,  but 
sufficiently  full  that  the  reader  can  definitely  determine 
the  species  studied  ;  and  it  gives  the  more  important  facts 
of  the  lives  of  our  butterflies. 

"  This  book  gives  the  unscientific  reader  a  direct  acquaintance 
with  a  large  number  of  species,  in  such  simple  terms  that  classi- 
fication is  not  difficult,  and  with  the  aid  of  profuse  colored  illustra- 
tions that  excite  the  admiration  of  those  who  have  contented  them- 
selves heretofore  with  viewing  these  beautiful  creatures  on  the  wing. 
Butterfly  catching  is  regarded  by  many  as  a  cruel  pastime,  but  there 
are  ways  of  capturing  these  ephemerals  which  may  rightly  be  regarded 
as  humane  and  decent,  and  the  authors,  filled  with  an  abounding 
love  of  nature,  recommend  nothing  that  is  not  compatible  with  their 
beliefs.  Notes  of  the  habitat  of  each  species  and  the  facts  of  butter- 
fly life  are  given  abundantly,  and,  with  the  pictures,  form  an  unusu- 
ally important  book,  which  is  certain  to  widen  the  circle  of  those 
who  know  the  joys  of  butterfly  collecting. " —  The  Washington  Star. 

"  Such  blending  of  tints  would  seem  to  be  a  task  fit  for  the 
painter  only  instead  of  the  printer.  Investigation  reveals  the  fact 
that  the  work  is  a  veritable  treasure-house  of  information— perhaps 
the  most  carefully  prepared  volume  yet  placed  before  the  public 
dealing  with  the  subject  in  hand."— St.  Louis  Globe-Democrat. 

"  One  of  the  most  interesting,  valuable,  and  beautiful  of  all  the 
nature  books  published  this  spring." — Brooklyn  Standard- Union. 

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FRANK  M.  CHAPMAN'S  BOOKS, 


Bird  Studies  with  a  Camera. 

With  Introductory  Chapters  on  the  Outfit  and  Methods  of 
the  Bird  Photographer.  By  FRANK  M.  CHAPMAN,  Associate 
Curator  of  Vertebrate  Mammalogy  and  Ornithology  in  the 
American  Museum  of  Natural  History.  Illustrated  with 
over  100  Photographs  from  Nature  by  the  Author.  i2mo. 
Cloth,  $i  75. 

Bird-Life.    A  Guide  to  the  Study  of  our  Common  Birds. 

Edition  de  Luxe,  with  75  full-page  lithographic  plates, 
representing  100  birds  in  their  natural  colors,  after  draw- 
ings by  ERNEST  THOMPSON-SETON.  8vo.  Cloth,  $5.00. 

Popular  Edition  in  Colors.  I2mo.  Cloth,  $2.00  net ; 
postage,  18  cents  additional. 

Teachers'  Edition.  With  75  full-page  uncolored  plates 
and  25  drawings  in  the  text,  by  ERNEST  THOMPSON- 
SETON.  Also  containing  an  Appendix  with  new  matter 
designed  for  the  use  of  teachers,  and  including  lists  of 
birds  for  each  month  of  the  year.  I2mo.  Cloth,  $2.00. 

Teachers'  Manual.  To  accompany  Portfolios  of  Colored 
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plates.  Sold  only  with  the  Portfolios,  as  follows : 

PORTFOLIO  No.  I.— Permanent  Residents  and  Winter 
Visitants.  32  plates. 

PORTFOLIO  No.  II.— March  and  April  Migrants.  34  plates. 

PORTFOLIO  No.  III.— May  Migrants,  Types  of  Birds' 
Eggs,  Types  of  Birds'  Nests  from  Photographs  from 
Nature.  34  plates. 

Price  of  Portfolios,  $1.25  each ;  with  Manual,  $2.00. 
The  three  Portfolios  with  Manual,  $4.00. 

Handbook    of    Birds    of   Eastern    North 
America. 

„  With  nearly  200  Illustrations.     i2mo.     Library  Edition. 
Cloth,  $3.00.     Pocket  Edition,  flexible  morocco,  $3.50. 

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By    WILLIAM    C.    EDGAR. 

The  Story  of  a  Grain  of  Wheat. 

By  WILLIAM  C.  EDGAR,  Editor  of  "  The  North- 
western Miller."  Illustrated.  Cloth,  $1.00  net ; 
postage,  10  cents  additional. 

The  story  of  wheat  is  a  marvelous  one,  and  is  here 
told  with  all  the  interest  of  a  narrative.  A  short  chapter 
dealing  with  the  character  of  the  berry  itself,  and  its  ene- 
mies, diseases,  and  pests,  precedes  its  earlier  history  from 
its  probable  birthplace  in  the  valley  of  the  Euphrates 
to  its  cultivation  in  modern  times.  Then  follows  a  re- 
view of  Britain's  supplies  and  requirements,  with  a  brief 
review  of  the  fields  of  France,  Germany,  and  other 
European  countries.  India  is  considered  as  a  wheat 
producer,  and  Russia's  ability  to  compete  in  the  world's 
markets  is  discussed. 

This  book  will  merit  the  attention  of  the  general 
reader  who  may  not  be  practically  interested  in  wheat 
and  its  products,  because  of  its  direct  and  lucid  narra- 
tive, telling  the  story  which  appeals  to  all  human  kind — 
the  story  of  man's  long-continued  struggle  for  plenty 
and  his  final  triumph  over  savagery  and  want.  Its 
special  and  exceptional  value,  however,  beyond  its  in- 
trinsic worth,  will  be  to  those  who  are  concerned  directly 
or  remotely  in  the  making  of  flour,  its  handling  and  sale, 
or  its  manufacture  into  bread.  By  these  it  will  be  wel- 
comed as  a  book  of  record  and  reference,  an  exponent 
of  the  fundamental  principles  of  their  particular  industry 
and  an  impartial  history  of  its  achievements,  written  by 
one  who  is  in  full  sympathy  with  its  broader  and  higher 
aspirations. 

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By  ARABELLA  B.  BUCKLEY  (Mrs.  Fisher). 


The  Fairy-Land  of  Science. 

With  74  Illustrations.  Revised  edition.  I2mo. 
Cloth,  gilt,  $1.50. 

Through  Magic  Glasses. 

A  Sequel  to  "  The  Fairy-Land  of  Science."  Illus- 
trated. I2mo.  Cloth,  $1.50. 

Life  and  Her  Children. 

Glimpses  of  Animal  Life  from  the  Amoeba  to  the 
Insects.  With  over  100  Illustrations.  I2mo.  Cloth, 
gilt,  $1.50. 

Winners  in  Life's  Race;    or,  The  Great 

Backboned  Family. 

With  numerous  Illustrations.  I2mo.  Cloth,  gilt, 
$1.50. 

A  Short  History  of  Natural  Science  and 
of  the  Progress  of  Discovery, 

From  the  Time  of  the  Greeks  to  the  Present  Time. 
New  edition,  revised  and  rearranged.  With  77  Illustra- 
tions. I2mo.  Cloth,  $2.00; 

Moral  Teachings  of  Science. 

I2mo.     Cloth,  75  cents. 
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UNIVERSITY  OF  CALIFORNIA  LIBRARY 

Los  Angeles 
This  book  is  DUE  on  the  last  date  stamped  below. 


DEC1119CT 


NOV  27  1967 


ED./  PSYC;, 
LIBRARY 


IB,'  JON  23 

j 

"APR  1 9 1978 


RENEWAL' 
ID  URL 


Form  L9-17m-8,-55(B3339s4)444 


UC  SOUTHERN  REGIONAL  LIBRARY  FACILITY 

•••••111 

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